The present invention relates to a device with a drafting device for drafting at least one sliver supplied to the drafting device. The device comprises a sliver depositing apparatus downstream from the drafting device for depositing the drafted sliver into a can as well as comprises a can replacement device for replacing a filled can with a can to be filled. The filled can is pushed from the filling position to an ejection position.
There is the danger in traditional devices with a drafting device, conditioned by strong temperature differences in the course of the drafting of at least one sliver, that after the sliver has been deposited in the can the moisture contained in the air and/or in the sliver condenses in the can.
As a result of the compression of the fibrous material on parts of the drafting device and friction on the roller pairs, the temperature of the fibrous material sharply rises when running through the drafting device. The fibrous material is subsequently deposited into a ready can. The can is pushed into an ejection position after it has been filled, where the fibrous material is relaxed and a high degree of sliver fungus is thus avoided. During the relaxing the moisture contained in the fibrous material evaporates into the air contained in the can. The uppermost sliver layers of the fibrous material deposited in the can make contact with the machine parts covering the can, so that the space inside the can is largely closed. When the air contained in the can meets these machine parts, which as a rule have a lower temperature, the air cools off so that the relative moisture of the air rises. If the air reaches the saturation limit (dew-point curve or saturation line in a state diagram (Mollier diagram) for moist air), a condensation of water occurs on the cited machine parts. This has the result that the moisture collects on these machine parts, from which it drips onto the fibrous material deposited in the can and thoroughly moistens it, which results in significant disturbances in the further processing.
Furthermore, devices with a drafting device that fill rectangular cans are known in the state of the art. These filled cans are directly ejected without a relaxation phase so that a condensation of the moisture contained in the fibrous material does not occur on adjacent machine parts here. However, these devices have the disadvantage that the filling amount of the can must be more sharply limited on account of the high band fungus produced.
If another sliver-producing apparatus, e.g., a card, is connected in front of the drafting device, the fibrous material has an elevated temperature at the drafting input already. The temperature of the fibrous material at the exit from the drafting is consequently also higher so that the danger of condensation of the moisture contained in the deposited sliver is especially great in this instance.
The present invention has the problem of creating a device with a drafting device that largely prevents in a simple manner a condensation of water on machine parts covering the cans.
This problem is solved by the features of the independent claims.
The invention relates to devices with a drafting device as well as to combinations of such devices with other equipment producing sliver. A device with a drafting device for drafting at least one sliver supplied to the drafting device comprises a sliver depositing apparatus arranged downstream from the drafting device for depositing the resulting, drafted sliver into a can. Furthermore, the device contains a can replacement device for replacing a filled can by a can to be filled. The filled can is pushed from the filling position to an ejection position. According to the invention means are provided on the device for lowering the temperature and/or the relative moisture of the fibrous material before or after its deposition in the can. In addition to or also instead of these means, means can be provided that raise the temperature of the machine parts that make contact with the uppermost sliver layers in the filled can located in the exit position. Accordingly, means for raising the temperature of the machine part are provided on a machine part in accordance with the invention, e.g., a plate of the carrier frame which plate contacts the uppermost sliver layers. To this end the machine part can comprise, e.g., a heating installation, especially a heating foil.
The state of the air located in the can or the state of the environment or of the adjacent machine parts can be varied in such a manner by the means of the invention that a condensation of water or on the machine parts in contact with the uppermost sliver layers is at least partially reduced. This means in the presentation of these means in a state diagram that the saturation line or dew-point curve is no longer dropped below during the change of state of the moist air in the can during the relaxation. The means of the invention can be provided individually or also in combination with each other so that the state of the air present in the can as well as the state of the environment can be changed and thus a dropping below the dew-point curve can be prevented in an even more reliable manner. This can largely prevent the condensation of the water contained in the moist air. The means for lowering the temperature and/or the relative moisture of the fibrous material can be provided before or after the depositing of the fibrous material in the can.
If the means for lowering the temperature and/or the relative moisture of the fibrous material are arranged after the drafting device the invention can be implemented in an especially simple manner. In particular, these means can be readily retrofitted on traditional devices.
If a sliver-producing apparatus, in particular a card, is connected in front of the drafting device which apparatus directly supplies an individual sliver to the drafting device without an intermediate depositing, the temperature difference between the air temperature in the can and the ambient temperature is especially large so that the danger of a condensation of water on machine parts is increased. The means in accordance with the invention can be used especially effectively in such a device.
The means in accordance with the invention can also be used especially advantageously if the device is designed as a draw frame with a card in front of it as sliver-producing apparatus. Moreover, the use of this means in a compound machine consisting of a drafting device and a sliver-producing apparatus is advantageous.
An advantageous embodiment of the invention provides that the means for increasing the temperature of said machine parts comprises at least one heating apparatus. The temperature of the machine parts can be raised by the heating apparatus in such a manner that this temperature and thus the point of the state of the air after cooling off is raised over the dew-point curve in the state diagram for moist air. During the cooling off of the air contained in the can from its initial state to the ambient temperature when meeting the cited machine parts the dew-point curve is therefore no longer dropped below and a condensation of water is thus prevented.
It is advantageous if the heating apparatus comprises at least one heating foil. The temperature of the machine parts in contact with the uppermost sliver layers can be increased in an especially simple manner with such a heating foil.
In order to be able to operate the heating apparatus in an especially economical and energy-saving manner, it is advantageous if the temperature of said machine parts can be controlled or regulated by the heating apparatus.
It is especially advantageous if the heating apparatus is arranged between a plate of the carrier frame and the machine part that is designed in an areal manner and makes contact with the uppermost layers of the sliver. This makes it possible to heat in an energy-saving manner only the layer that makes contact with the fibrous material and/or the air in the can. This can avoid a flow-off of heat via the plate of the carrier frame into the carrier frame.
The machine part in contact with the uppermost layers of the sliver is preferably designed as a sliding sheet, e.g. in the form of a noble-steel plate or a ceramic plate. It is also advantageous if the machine part is designed as a coating or some other covering of the carrier frame plate. This significantly facilitates the shifting of the filled cans from the filling position into an ejection position since the uppermost sliver layers can slide along the sliding sheet.
Another advantageous further development of the invention provides that at least one passage opening that communicates with the ambient air is provided in the machine part that contacts the uppermost layers of the sliver. As a result, moisture can escape from the can during cooling off and a state of equilibrium of the air in the can with the ambient air is adjusted that is between the state of the air in the can and that of the ambient air. This state of equilibrium is also above the dew-point curve, given appropriate parameters of the ambient air, in the state diagram so that this also makes it possible to avoid a condensation of water.
It is furthermore advantageous is the passage opening is connected to an apparatus for supplying room air or conditioned air, e.g., from an air conditioning unit, in the inner space of the can. This makes possible an improved dehumidifying and cooling off of the air in the can. If appropriately conditioned air is brought into the inner space of the can via the apparatus the state of equilibrium that is adjusted can be reliably brought above the dew-point curve, even if the ambient air has unfavorable climatic conditions, e.g., elevated air moisture or temperature.
A machine part in accordance with the invention with a passage opening can be attached in an especially simple manner to the device or to the carrier frame plate. No changes to the device or to the can replacement device are required for this but rather only a replacing of the corresponding machine part is required. Likewise, such a passage opening can also be added subsequently to a traditional carrier frame plate or to an appropriate machine part, which can reduce problems caused by condensation in an especially simple and economical manner.
Another advantageous embodiment of the invention provides that the means for lowering the temperature and/or the relative moisture of the fibrous material before it is deposited in the can comprises at least one cooling apparatus. A cooling of the fibrous material is possible in this instance in front of, in and/or after the drafting device. The initial state of the air in the can be changed in such a manner by such a cooling apparatus that when the air meets adjacent machine parts the dew-point curve is also not dropped below.
The cooling apparatus advantageously cooperates with a structural component that makes contact with the fibrous material during operation of the device. As a result of the contact, the cooling of the fibrous material can take place in an especially efficient and energy-saving manner.
It is especially advantageous if the cooling apparatus is arranged on a sliver forming unit downstream from the drafting device in which unit the drafted fibers material is combined to a sliver. Consequently, the construction expense for such a cooling apparatus can be kept especially low. It is especially advantageous in this connection if the cooling apparatus is designed for supplying a gas or gaseous mixture that is cooler than the ambient temperature through bores or slits of the sliver forming unit. The cooling agent can be introduced through the bores or slits in an especially simple manner into the inner space of the sliver forming unit through which the fibrous material passes.
Another advantageous further development of the invention is characterized in that the cooling apparatus is arranged between the sliver-producing apparatus and the drafting device. The temperature of the sliver can be significantly lowered as a result already at the entrance into the drafting device.
It is also advantageous if the cooling apparatus comprises one or more Peltier elements. These can be used to cool defined areas, such as, in particular, structural components in contact with the fibrous material or the drafted sliver.
A combination in accordance with the invention of a card with a drafting device for drafting at least one sliver supplied to the drafting device directly from the card comprises a sliver depositing apparatus downstream from the drafting device for depositing the resulting drafted sliver into a can. Moreover, the combination in accordance with the invention comprises a can replacement device for replacing a filled can with a can to be filled, which filled can is pushed from the filling position to an adjacent replacement position. According to the invention no machine part covering and contacting the uppermost sliver layers is provided in the ejection position. As a consequence, an exchange of the air in the can with the ambient air is made possible so that after a compensation procedure a thermodynamic state of equilibrium is also adjusted that is above the dew-point curve.
Other advantages of the invention are described using the following exemplary embodiments.
a shows an embodiment of the invention with a heating apparatus and a corresponding state diagram.
a shows an alternative embodiment of means in accordance with the invention for avoiding a condensation of water and shows a corresponding state diagram.
a show another embodiment of means in accordance with the invention with an apparatus for supplying room air or conditioned air as well as a corresponding state diagram.
a show an alternative embodiment of the invention with a cooling apparatus for cooling fibrous material and show a corresponding state diagram.
A condensation of water in filled cans 6′ frequently occurs in traditional draw frames 2, especially in compound machines, conditioned by temperature changes in the course of the production process, which is explained in more detail with
The compressing of sliver FB on the feeler rollers and the drafting bring about an elevation of temperature of sliver FB so that drafted sliver FB′ has exit temperature TA upon leaving drafting device 3 that is higher than entrance temperature TE and significantly higher than ambient temperature TU. As a result of the evaporation of the moisture contained in the fibrous material the air in the inner hollow space 12 of deposited sliver FB′ after the depositing of the sliver has can temperature TK and relative moisture LFK.
If the air located in can 6 with temperature TK and a relative moisture LFK meets adjacent machine parts 13, 20 with the ambient temperature TU, e.g., a carrier frame plate 13 covering cans 6, during the relaxation phase, there is a danger of a condensation of the moisture contained in the air and/or in the fibrous material in corresponding devices of the state of the art. This has the consequence that water collects on the condensation surface, in this instance on plate 13, drips onto the fibrous material FB′ deposited in can 6′ and thoroughly moistens it.
A corresponding change of state of the air contained in can 6′ is schematically shown in a state diagram for moist air (Mollier diagram) according to
An embodiment of the invention in accordance with
If heating apparatus 21 is provided with a control-or regulating unit (not shown here) it can be operated in a particularly energy-saving and economical manner. To this end a sensor for temperature detection can be arranged on machine parts 13, 20.
Another embodiment of the invention (not shown) provides that no machine part 13, 20 or one covering the cans only partially is provided at least in ejection position 19. Even this makes possible a compensation procedure possible between state Z1 of the air in the can and state ZU of the environment. However, the entering of moisture into adjacent structural components must be avoided here.
The condensing of water and the thorough wetting of fibrous material FB′ in can 6′ can be suppressed in an especially effective manner if the passage openings are connected to an apparatus 25 for supplying room air or conditioned air, as
An especially efficient cooling of fibrous material FB can be achieved if cooling apparatus 27 cooperates with a structural component in direct contact with fibrous material FB. To this end, e.g., rollers 11 of drafting device 3 can be cooled or cooling apparatus 27 is arranged on sliver forming unit 5. Insert 28 for a fleece guidance nozzle (not shown) in a sliver forming unit 5, which insert makes possible the supplying of a cooling agent, is shown in
The invention is not limited to the exemplary embodiments shown. Numerous modifications of the invention and especially combinations are possible within the scope of the claims.
Number | Date | Country | Kind |
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10 2004 053 889.1 | Nov 2004 | DE | national |