Abstract:
A fiber processing machine includes a clothed roll entraining fiber material thereon; a roll cover circumferentially partially surrounding the roll and defining an annular clearance therewith; a transfer opening provided in the roll cover for admitting fiber material to the roll; a waste discharge opening provided in the roll cover for removing waste from the clearance; a fiber removal opening provided in the roll cover downstream of the waste discharge opening as viewed in the direction of roll rotation; an arrangement for generating an air stream for doffing fiber material from the roll and for discharging doffed fiber material through the fiber removal opening; an arrangement for varying a strength of the air stream at the fiber removal opening; and an arrangement for varying the extent of waste removal through the waste discharge opening.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
         [0001]    This application claims the priority of German Application No. 101 22 459.1 filed May 9, 2001, which is incorporated herein by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    This invention relates to an apparatus integrated in a fiber processing machine, such as a card, a cleaner, an opener or the like for fiber material such as cotton and chemical fibers. The fiber processing machine has roll cover elements associated with a rapidly rotating roll. Between the cover elements a plurality of openings are provided. A first opening serves for the discharge of foreign bodies, such as trash, seed fragments, leaf fragments and the like whereas a second opening which is arranged downstream of the first opening as viewed in the rotary direction of the roll, serves for discharging fiber material by an air stream.  
           [0003]    German patent document No. 1 114 127 describes an apparatus in which the fiber tufts, freed from a preponderant part of foreign bodies, are brought on a doffer in the effective zone of an air stream which carries the fiber tufts to a screening drum separator or a pneumatic transport device. The doffer has a sawtooth-like clothing whose teeth are inclined in the direction of roll rotation so that the fiber web attached to the teeth is readily removed by the suction air stream. The air stream is drawn from the outside through a gap. It is a disadvantage of such a prior art construction that it is not possible to vary the air stream. An outlet opening for the foreign bodies in the cover for the doffer is not present because the fiber material on the doffer has already been substantially cleaned.  
         SUMMARY OF THE INVENTION  
         [0004]    It is an object of the invention to provide an apparatus of the above-outlined type from which the discussed disadvantages are eliminated and which, in particular, makes possible a variation of the fiber-doffing air stream and also provides for an improved waste quality at an outlet opening.  
           [0005]    This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the fiber processing machine includes a clothed roll entraining fiber material thereon; a roll cover circumferentially partially surrounding the roll and defining an annular clearance therewith; a transfer opening provided in the roll cover for admitting fiber material to the roll; a waste discharge opening provided in the roll cover for removing waste from the clearance; a fiber removal opening provided in the roll cover downstream of the waste discharge opening as viewed in the direction of roll rotation; an arrangement for generating an air stream for doffing fiber material from the roll and for discharging doffed fiber material through the fiber removal opening; an arrangement for varying a strength of the air stream at the fiber removal opening; and an arrangement for varying the extent of waste removal through the waste discharge opening.  
           [0006]    By setting the strength of, the air stream for removing the fiber material at the fiber removal opening, it is feasible to improve the waste quality at a separating location situated upstream of the fiber removing location. It is a particular advantage of the invention that an adjustment of the air stream also affects the vacuum between the cover and the roll, and thus the intensity of the removal of foreign bodies at the waste discharge opening is improved. In this manner the ratio between the desired separation of foreign bodies and an undesired separation of good fibers is optimized. It is in particular feasible to ensure, to the extent possible, a minimum loss on good fibers in the foreign body separating process. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a schematic side elevational view of a four-roll cleaner incorporating the invention.  
         [0008]    [0008]FIG. 2 is a schematic fragmentary sectional side elevational view of a three-roll cleaner incorporating the invention.  
         [0009]    [0009]FIG. 3 is an enlarged detail of FIG. 2, showing a regulator and setting member for a flow rate setting element.  
         [0010]    [0010]FIG. 3 a  is a fragmentary side elevational view of a fiber processing roll and the cover element associated therewith to illustrate the vacuum air stream.  
         [0011]    [0011]FIG. 4 is as schematic perspective view of a suction hood arranged immediately downstream of a location where foreign bodies are separated.  
         [0012]    [0012]FIG. 5 is a side elevational view of a variant of the FIG. 2 construction. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]    [0013]FIG. 1 illustrates a four-roll cleaner  1  which may be a CVT 4 model manufactured by Trützschler GmbH &amp; Co. KG, Mönchengladbach, Germany. The fiber material is introduced into the nip of cooperating feed rollers  1   a ,  1   b  which clamp the material and advance it to a pin roll  2 , having a circumferential velocity of approximately 10-21 m/sec. From the pin roll  2  the material is transferred to a sawtooth roll  3 , having a circumferential velocity of approximately 15-25 m/sec. The sawtooth roll  3  is followed by additional sawtooth rolls  4  and  5 . The rolls  2 - 5  have a diameter of approximately 150-300 mm and are enclosed in a cleaner housing  7 . The roll  5  is associated with a stationary carding element  8 , an adjustable guide element  9 , an air and waste discharge opening  10 , a separating knife  11  and a pressure sensor  12 . The separating knife  11  is adjoined by a suction hood  13 . The pressure sensor  12  and the adjustable guide element  9  may be connected to an electronic control and regulating device, such as a microcomputer, as illustrated in FIG. 3. The roll  5  is surrounded by a cover which is composed of a plurality of arcuate cover elements  14   a ,  14   b ,  14   c  and  14   d . Between the cover elements  14   d  and  14   c  the waste discharge opening  10  is provided through which foreign bodies and other impurities are separated from the fiber material. Between the cover elements  14   c  and  14   b  a fiber removal opening  15  is provided, through which the fiber material is taken off the roll  5  by an air stream B 1 , B 2 . Between the cover elements  14   a  and  14   d  a transfer opening is provided to allow transfer of the fiber material from the roll  4  to the roll  5 . The roll  5  is associated with a pneumatic fiber removal device which comprises a duct  16  merging into the opening  15  bordered by a circumferential portion of the roll  5 . The duct  16  has an air supply duct portion  16   a  through which an air stream B 1  is drawn for contacting the circumferential portion of the roll  5  exposed in the opening  15 . The air supply duct portion  16   a  is adjoined by an air removal duct portion  16   b  through which a fiber/air mixture B 2  is drawn away from the roll  5 . The duct portion  16   b  is coupled to a non-illustrated vacuum source. As shown in FIG. 1, the air stream B 1 , B 2  flows substantially downward from above. At the upstream end of the opening  15  an air flow rate setting element (guide vane)  17  is disposed which is pivotally supported for swinging motions in the direction of arrows C and D. By means of the air flow rate setting element  17  the strength of the fiber doffing air stream B 1 , B 2  is adjustable and thus the degree of separation of foreign bodies through the waste discharge opening  10  may be controlled. The strength of the air stream B 1 , B 2  depends from the flow rate and/or the air speed and/or the air pressure.  
         [0014]    [0014]FIG. 2 partially shows a three-roll cleaner which may be a CXL 3 model manufactured by Trützschler GmbH &amp; Co. KG. The air stream B 1 , B 2  serving for removing the fiber material from the roll  4  flows essentially from below upwardly through the duct  16 . By means of the air flow rate setting element  17  the strength of the air stream is affected by virtue of a throttle effect. While in the illustrated construction the flow rate of the air stream B 1  in the duct portion  16   a  is set, the air stream B 2  and the vacuum stream G (FIG. 3 a ) between the cover portion  14   f  and the surface of the roll  4  are also changed. The waste discharge opening  10  is in communication with a suction hood  24  and is bordered by a separating knife  23 . By virtue of this arrangement the air supply in the region of the fiber removal opening  15  may be adjusted. At the same time an adjustable vacuum is provided immediately downstream of the waste discharge opening  10 .  
         [0015]    Turning to FIG. 3, a pressure sensor  18  is arranged upstream of the air-doffer (fiber removal) opening  15  and the air flow rate setting element  17 , as viewed in the direction of rotation  4   b  of the roll  4 . The pressure sensor  18  detects the static pressure prevailing in the annular clearance a between the cover element  14   f  and the roll clothing  4   a . The sensor  18  communicates with the annular clearance a via a through bore  18 ′ provided in the cover element  14   f . The measured pressure values are utilized for setting the distance b of the setting element  17  from the points of the roll clothing  4   a . Such a setting may be effected manually or automatically as a function of the measured values supplied by the pressure sensor  18 . For such an automatic regulation the pressure sensor  18  applies its signals to a transducer  19  which converts the pressure values into electric signals. The transducer  19 , in turn, applies its signals to a regulator  20  which is provided with a nominal value setter  21 , for example, a microcomputer. The regulator  20  is connected with the adjustable guide element  17  by means of a setting member such as a stepping motor  22 . In the regulator  20  the actual pressure values are compared with the nominal pressure values and, in case of a deviation, setting signals are applied to the element  17  by the stepping motor  22 . The air flow rate setting element  17  journals in a support  17   a  and is thus rotatable in the direction of the arrows C, D. In addition to adjusting the clearance b as noted earlier, the guide element  17  also varies the clearance c between the guide element  17  and the facing portion of the inner wall of the duct  16 .  
         [0016]    By setting the strength of the air stream B 1 , B 2  for doffing the fiber material through the fiber removal opening  15 , it is feasible to improve, apart from the change of degree in the fiber doffing, the waste quality at the waste discharge opening  10  situated upstream of the fiber removal opening  15 . It is a particular advantage of this arrangement that by virtue of adjusting the air stream, the vacuum between the cover (designated at  14   c  in FIG. 1 and at  14   f  in FIG. 2) and the respectively last roll  5  or  4  thus has an effect on the intensity of the separation of foreign bodies through the opening  10 . In this manner, the ratio between the desired separation of foreign bodies and the undesired separation of good fibers is optimized. It is in particular possible to keep the loss of good fibers at a minimum during the foreign body separation.  
         [0017]    The presence of vacuum downstream of the respective separating knife  11  and  23  is advantageous to ensure that a separation of good fibers through the waste removal opening  10  is kept at a minimum. Such a vacuum is generated by the air stream passing through the fiber removal opening  15  with the air-doffed fiber material. By throttling the air admission to the air stream which carries the fiber material through the opening  15 , the vacuum may be varied behind the separating knife and thus the waste quality of the last separating location (waste discharge opening  10 ) may be affected. The vacuum is generated by the air stream G shown in FIG. 3 a.    
         [0018]    Each waste separating location which is not followed by a suction location for the fiber material may be complemented by a suction hood in which a vacuum stream is generated by a vacuum source attached to the suction hood. The strength of the generated vacuum may be adjusted by an appropriate setting element or may be regulated. Such an arrangement is shown in FIG. 4 and may be incorporated in the FIG. 1 cleaner, at the roll  3  which is associated with a waste separating opening  10 , a separating knife  25  and a suction hood  26 . As seen in FIG. 4 and viewed in the direction of rotation of the roll  3 , downstream of the waste discharge opening  10  an air passage opening  27  is arranged which is adjoined by a suction hood  28 . A throttle slide  29  arranged at an end of the suction hood  28  is movable in the direction E, F to vary the flow passage cross section for the drawn air. The suction hoods  26  and  28  are coupled to non-illustrated suction sources. Through the suction hood  28  solely air (that is, no fiber material) is withdrawn.  
         [0019]    [0019]FIG. 5 shows a fiber processing machine similar to that illustrated in FIG. 2 except it is not provided with a separating location for foreign bodies. Such a fiber processing machine may be a chemical fiber opener. By virtue of the adjustable air flow rate setting element  17  the strength of the fiber doffing air stream B 1  and B 2  may be varied.  
         [0020]    The features according to the invention described in connection with roll  5  of the four-roll cleaner of FIG. 1 and the three-roll cleaner of FIG. 2 may find application at a licker-in and/or a main carding cylinder of a carding machine.  
         [0021]    It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.