EP3184679A1 - Method for operating an open-ended rotor spinning device and open ended rotor spinning machine with a multitude of open-ended rotor spinning devices side by side - Google Patents

Abstract

The present invention relates to a method for operating an open-end rotor spinning device (1). For spinning, a rotor housing (2) is closed with a cover element (8) and subjected to negative pressure by means of a vacuum supply (10), a spinning rotor (3) rotates in the rotor housing (2) and a projection (12) attached to the cover element (8) ) with a thread withdrawal channel (15) protrudes into the spinning rotor. When braking the spinning rotor (2), the rotational speed of the spinning rotor (2) is reduced, the negative pressure in the rotor housing (2) above a first speed (n 1), in which the centrifugal forces a fiber ring (5) still safe in the rotor groove ( 4) of the spinning rotor (3) hold, and the fiber ring (5) by displacement of the cover element (8) between an open position and a closed position below a second speed (n 2), wherein the fiber ring (5) due to the decreasing centrifugal forces already collapsed, sucked due to the in the rotor housing (2) restored negative pressure. The present invention also relates to an open-end rotor spinning machine for carrying out the method.

Description

The present invention relates to a method of operating an open-end rotor spinning device and an open-end rotor spinning machine having a plurality of juxtaposed open-end rotor spinning devices.

Open-end rotor spinning machines have a multiplicity of workstations arranged next to one another. At the jobs, an open-end rotor spinning device is arranged in each case. An open-end rotor spinning device comprises a rotor housing with a cover element for closing the rotor housing. In the rotor housing, a spinning rotor is arranged. The spinning rotor is rotatably mounted. The spinning rotor can be driven for spinning in various ways. It is known to drive the spinning rotors of several open-end rotor spinning devices via a common drive. The force can be transmitted from the common drive to the spinning rotors, for example by means of a belt. It is also known that each spinning rotor is associated with an electric motor single drive. In connection with a single drive, the spinning rotor is preferably mounted without contact. A non-contact storage may be formed as a magnetic storage. Contactlessly mounted spinning rotors with individual drives are particularly sensitive to contamination.

For spinning, a negative pressure in the rotor housing is required. Therefore, known open-end rotor spinning machines have a central vacuum source and a machine-length vacuum line. The vacuum supply of the open-end rotor spinning devices is realized by a connection of the rotor housing to the machine-length vacuum line.

In spinning operation, fiber material is introduced into the rotor housing via a fiber guide channel, and the finished spun yarn is withdrawn from the rotor housing via a yarn withdrawal channel. The spinning rotor-side end of the thread take-off channel is located on a projection which is fixed to the lid member and projects into the spinning rotor.

The DE 10 2004 016 547 B4 discloses a method for cleaning a spinning rotor. The cleaning is already carried out on the spinning or outgoing spinning rotor. For this purpose, the lid member of the rotor housing is automatically opened by means of a movable maintenance device and the spinning rotor delivered a cleaning device, wherein a minimum speed of the spinning rotor is not exceeded. In the rotor groove of the spinning rotor fiber rings collect, which are held by the centrifugal forces in the rotor groove. The cleaning device should engage before a fiber ring comes loose from the rotor groove. Such a cleaning device can, for example, seal the outer annular space surrounding the spinning rotor and thus prevent leakage of the fibers. The process is intended to prevent fiber from laying around the neck with the thread withdrawal channel and being pulled out of the spinning rotor when the cover element is opened.

Moreover, when braking the spinning rotor, not only can fibers be laid around the neck with the yarn withdrawal channel, but the fibers can move between the outer wall of the spinning rotor and the neck when the cover element is closed and pass behind the spinning rotor. The fibers can then soil the bearing and failure of the open-end rotor spinning devices can occur. Electromotive individual drives, which are arranged behind the spinning rotor, are also particularly sensitive to soiling. With contactless bearings, contamination of the bearing air gap can quickly lead to errors.

That in the DE 10 2004 016 547 B4 Although described method would prevent contamination of the drive and storage; however, the cleaning device is relatively expensive and at each braking operation, the maintenance device would first have to be positioned in front of the open-end rotor spinning device.

It is therefore the object of the present invention to prevent in a simple manner that lay down when braking the spinning rotor fibers around the neck with the yarn draw-off.

To achieve the object, a method for operating an open-end rotor spinning device is proposed. For spinning a rotor housing is closed with a cover element and applied by means of a vacuum supply with negative pressure, a spinning rotor rotates in the rotor housing and a stop attached to the lid member protrudes with a yarn withdrawal channel in the spinning rotor. When braking the spinning rotor, the rotational speed of the spinning rotor is reduced, the negative pressure in the rotor housing is above a first speed at which the centrifugal forces still hold a fiber ring in the rotor groove of the spinning rotor, and the fiber ring is displaced by shifting the lid member between an open position and a closed position below a second speed at which the fiber ring due to the decreasing. Centrifugal forces has already collapsed, sucked due to the restored negative pressure in the rotor housing.

As already explained, when the spinning rotor is braked in the closed rotor housing, fibers surround the approach projecting into the spinning rotor. The reason for this, however, is not alone in the decreasing centrifugal forces and the positioning of the approach in the interior of the spinning rotor; rather, the flow conditions in the closed rotor housing have a decisive influence. For spinning, a negative pressure must prevail in the rotor housing; when braking this vacuum is a problem. The negative pressure ensures that air flows into the rotor housing via the spinning-technologically necessary openings in the rotor housing, in particular through the thread withdrawal channel. This results in the rotor housing an air flow from the interior of the spinning rotor past the approach out of the spinning rotor. Fibers dropped out of the rotor groove due to the decreasing centrifugal forces move along the air flow. The residual rotation of the spinning rotor still supports this movement.

The inventive method begins with this knowledge. Accordingly, the negative pressure in the rotor housing should be canceled before the centrifugal forces no longer hold a fiber ring located in the rotor groove in the rotor groove. By releasing the negative pressure, the air flow described above is suppressed. A collapsing due to the decreasing centrifugal forces fiber ring thus remains in the interior of the spinning rotor. Unlike the description in the prior art, it is therefore not necessary for a cleaning device to engage as quickly as possible. Rather, the fibers located in the interior of the spinning rotor can later be sucked off in a simple manner by a displacement of the cover element with restored negative pressure. Thus, the inventive method requires no additional cleaning device. The displacement of the cover element can be done by an adjusting device at the workplace.

During the displacement of the cover element between an open position and a closed position, a position of the cover element is traversed, in which the cover element is opened so far that sufficient space between the approach and the spinning rotor is present, and the lid member is closed so far that a sufficient Negative pressure prevails in the rotor housing to suck the fibers.

The displacement of the cover element can be done while the spinning rotor is still rotating or when the spinning rotor is already stationary. The important thing is that the second speed, at which the fiber ring has already collapsed, is below. Otherwise, the displacement would be counterproductive and would do exactly what the present invention is intended to prevent, namely that fibers lay around the neck.

To cancel the negative pressure in the rotor housing above the first speed, two alternatives are conceivable in principle.

One possibility is the displacement of the cover element in the open position. Even if the vacuum supply further sucks air from the rotor housing, the air is supplied immediately via the opening, so that there is no negative pressure in the rotor housing.

The other option is to switch off the vacuum supply of the open-end rotor spinning device. When switching off the vacuum supply, the lid member may initially remain closed. Switching off the vacuum supply has the advantage that a vacuum source of the open-end rotor spinning machine is less stressed and energy is saved. The energy consumption of the vacuum source is significantly higher with an open rotor housing than with a closed rotor housing.

According to a possible embodiment of the method according to the invention, the cover element for sucking the collapsed fiber ring below the second speed with effective vacuum supply from the open position in the Closed position is transferred. This process step can be carried out independently of the previous history. Was the cancellation of the negative pressure in the rotor housing achieved by opening the lid member, without the negative pressure supply has been switched off, the vacuum supply is effective and the lid member can be transferred directly to the closed position. If the cancellation of the negative pressure was achieved by switching off the vacuum supply, the cover element can be opened at some point. As long as the vacuum supply is turned off, the opening of the cover element has no effect. Before closing the cover element, however, the vacuum supply must be switched on again so that the collapsed fiber ring is also sucked off when closing.

Alternatively, the collapsed fiber ring can also be sucked off by the cover element is transferred below the second speed with effective vacuum supply from the closed position to the open position. Such an approach is particularly useful if the release of the negative pressure by switching off the vacuum supply has been achieved. The vacuum supply must then be turned on again before opening, preferably at a standstill of the spinning rotor.

The object is also achieved by an open-end rotor spinning machine for carrying out the method according to the invention with a plurality of juxtaposed open-end rotor spinning devices. The open-end rotor spinning devices each have a rotor housing, a spinning rotor arranged in the rotor housing, a cover element for closing the rotor housing, which is displaceable between an open position and a closed position, an adjusting device for displacing the cover element between the open position and the closed position, one on the cover element fastened approach with a thread withdrawal channel which projects into the spinning rotor in the closed position, and a vacuum supply for acting on the rotor housing with negative pressure. For carrying out the method according to the invention, a control device is designed to control one or more open-end rotor spinning devices during braking of the spinning rotor such that the negative pressure in the rotor housing above a first rotational speed at which the centrifugal forces still hold a fiber ring in the rotor groove of the spinning rotor becomes. Furthermore, the control device is designed to control one or more open-end rotor spinning devices in such a way that the fiber ring is displaced the cover element between the open position and the closed position below a second speed at which the fiber ring has already collapsed due to the decreasing centrifugal forces, is sucked due to the restored negative pressure in the rotor housing.

According to a preferred embodiment, the control device for canceling the negative pressure is designed to control the adjusting device above the first rotational speed in such a way that the cover element is displaced into the open position.

According to another embodiment, a valve for switching off the vacuum supply is provided and the control device is designed to close the valve to switch off the vacuum supply above the first speed.

According to a development of the open-end rotor spinning machine according to the invention, the control device is designed to control the adjusting device so that the cover element is transferred below the second speed with effective vacuum supply from the open position to the closed position.

The control device may also be designed to control the adjusting device such that the cover element is transferred from the closed position to the open position below the second rotational speed when the vacuum supply is effective.

The invention will be explained in more detail with reference to an embodiment shown in the drawings.

Fig. 1

eine Seitenansicht einer Offenend-Rotorspinneinrichtung einer erfindungsgemäßen Offenend-Rotorspinnmaschine;

Fig. 2

eine Darstellung der Strömungsverhältnisse in einem Spinnrotor

Fig. 3

Drehzahlverlauf beim Bremsen des Spinnrotors.

Show it:

Fig. 1

a side view of an open-end rotor spinning device of an open-end rotor spinning machine according to the invention;

Fig. 2

a representation of the flow conditions in a spinning rotor

Fig. 3

Speed curve during braking of the spinning rotor.

In the Fig. 1 Open-end rotor spinning device of an open-end rotor spinning machine has the reference numeral 1 as a whole. Such open-end rotor spinning devices each have, as is known, a rotor housing 2 in which a spinning rotor 3 rotates at high speed n. The spinning rotor 3 is rotated by an electric motor single drive 33 in rotation. The drive 33 simultaneously includes the magnetic bearing of the spinning rotor 3.

How out Fig. 1 it can be seen, the rotor housing 2 open towards the front itself during the spinning operation by a pivotally mounted lid member 8, in which a (not shown) channel plate is embedded with a seal 9, closed.

The rotor housing 2 is also connected via a corresponding vacuum line 10 to a vacuum source 11, which generates the spinning vacuum required in the spinning process in the rotor housing 2. The vacuum line 10 forms the vacuum supply of the open-end rotor spinning device 1. The negative pressure source 11 also supplies the other open-end rotor spinning devices of the open-end rotor spinning machine. In order to switch off the vacuum supply when needed, the vacuum line 10, a valve 31.

In the cover element 8, a projection 12 is arranged, which has the rotor-side end 13 of the thread withdrawal channel 15 and the mouth region of the fiber guide channel 14. In addition, an opening roller housing 17 is fixed to the lid member 8, which is mounted rotatably limited about a pivot axis 16. Furthermore, the cover element 8 has individual drives 19, 20 for an opening roller 21 or a sliver retraction cylinder 22 on the rear side.

To open and close the lid member 8 is formed on the open-end rotor spinning device 1 designed as a pneumatic cylinder actuator 32 is present. The Fig. 1 shows the lid member in a closed position. By extending the pneumatic cylinder 32, the lid member 8 pivots about the pivot axis 16 of the rotor housing 2 away. The cover element 8 can thus be transferred to an open position. For an open position for the purposes of the present invention, it is not essential that the spinning rotor be accessible without hindrance. It is sufficient if the ambient air can penetrate unhindered. This is achieved in that the seal 9 is completely spaced from the rotor housing 2.

The open-end rotor spinning device 1 is assigned a control device 34. The controller 34 controls the actuator 32 and the valve 31 as needed. In the illustrated embodiment, the control device 34 is also designed to control the electric motor single drive 33. The controller 34 may have connections to other elements of the workstation or open-end rotor spinning machine.

In Fig. 2 is the spinning rotor 3 and projecting into the spinning rotor 3 approach 12 with the Fadenanzugskanal 15 shown only schematically to illustrate the flow conditions in the spinning rotor 3. During spinning, the spinning rotor 3 on the in Fig. 2 Not shown Faserleitkanal 14 fed to a sliver. The fibers form a fiber ring 5 in the rotor groove 4. The fibers collected in the rotor groove 4 are continuously incorporated into the thread end and the thread is withdrawn through the thread withdrawal channel 15. When stopping the open-end rotor spinning device, for example after a yarn breakage, the fiber ring 5 initially remains in the rotor groove 4 due to the centrifugal forces. When the spinning rotor 3 brakes, the centrifugal forces decrease correspondingly as the speed decreases. With the cover element 8 closed and effective vacuum supply 10, that is, with the valve 31 open, air is sucked into the rotor housing 2 through the thread withdrawal channel 15. The arrows 40 indicate the resulting air flow. If the centrifugal forces no longer hold the fiber ring 5 in the rotor groove 4, the air flow 40 brings the fiber ring 5 from the rotor groove 4 in the area between the projection 15 and the side walls 41 of the spinning rotor 3. In this area is located in Fig. 2 the fiber ring 5 '. The rotation of the spinning rotor 3, the fibers screw around the neck 12. Thus, the fibers can move out of the interior of the spinning rotor and can pass through the spinning rotor 3 in the area behind the rear wall 42 of the spinning rotor. From there, the fibers enter the drive 33. This is the aim of the present invention.

In the following, the inventive method will be explained again. The Fig. 3 shows a curve of the rotational speed n during braking of the spinning rotor 3, plotted over time t. The spinning rotor 3 initially rotates at the spinning speed n ₀ . The speed n is reduced, passing the speed n ₁ . The rotational speed n ₁ is set so that the centrifugal forces keep the fiber ring 5 at this speed still safe in the rotor groove 5. Above the speed n ₁ , the negative pressure in the rotor housing is released. There are basically two options. The cover element 8 can be opened by means of the adjusting device 32, or the vacuum supply 10 is switched off by closing the valve 31. The control of the adjusting device 32 or the valve 31 by means of the control device 34. At the speed n _{2 of} the fiber ring 5 has already collapsed due to the decreasing centrifugal forces. The fibers remain in the interior of the spinning rotor 3. Below the speed n ₂ , the fibers of the collapsed fiber ring 5 can be sucked off in the manner already described by displacement of the cover element 8. Also for this purpose, the control of the adjusting device 32 and / or the valve 31, the control device 34th

The speeds n ₁ and n ₂ are dependent on different sizes, in particular on the rotor diameter, but also on the processed fiber material. The rotational speeds at which the negative pressure is released and the fibers are sucked off can be determined in terms of parts and stored in the control device 34.

Claims (10)

Method for operating an open-end rotor spinning device (1)
being for spinning
a rotor housing (2) is closed with a cover element (8) and subjected to negative pressure by means of a vacuum supply (10),
a spinning rotor (3) rotates in the rotor housing (2) and
a projection (12) fastened to the cover element (8) with a thread withdrawal channel (15) protrudes into the spinning rotor (3),
and wherein during braking of the spinning rotor (3)
the speed of the spinning rotor (2) is reduced,
the negative pressure in the rotor housing (2) above a first rotational speed (n ₁ ) at which the centrifugal forces still hold a fiber ring (5) in the rotor groove (4) of the spinning rotor (3), and
the fiber ring (5) by displacement of the cover element (8) between an open position and a closed position below a second speed (n ₂ ), in which the fiber ring (5) has already collapsed due to the decreasing centrifugal forces, due to in the rotor housing (2) recovered vacuum is sucked. A method according to claim 1, characterized in that the negative pressure above the first rotational speed (n ₁ ) is canceled by displacement of the cover element (8) in the open position. Method according to one of claims 1 or 2, characterized in that the negative pressure above the first rotational speed (n ₁ ) by switching off the vacuum supply (10) of the open-end rotor spinning device (1) is canceled. Method according to one of the preceding claims, characterized in that the cover element (8) below the second rotational speed (n ₂ ) is transferred from the open position to the closed position with effective negative pressure supply (10). Method according to one of claims 1 to 3, characterized in that the cover element (8) below the second rotational speed (n ₂ ) is transferred from the closed position to the open position with effective negative pressure supply (10). Open-end rotor spinning machine with a plurality of juxtaposed open-end rotor spinning devices (1),
the open-end rotor spinning devices (1) each having a rotor housing (2),
a spinning rotor (3) arranged in the rotor housing (2),
a cover element (8) for closing the rotor housing (2), which is displaceable between an open position and a closed position,
an adjusting device (32) for displacing the cover element (8) between the open position and the closed position,
a projection (12) fixed to the cover element (8) with a thread withdrawal channel (15) which projects into the spinning rotor (3) in the closed position, and
a vacuum supply (10) for acting on the rotor housing (2) with negative pressure,
wherein a control device (34) is adapted to one or more open-end Rotorspinneinrichtungen (1) during braking of the spinning rotor (3) to control so that the negative pressure in the rotor housing (2) above a first speed (n ₁ ), wherein the Centrifugal forces a fiber ring (5) still in the rotor groove (4) of the spinning rotor (3) hold, is repealed and that the fiber ring (5) by displacement of the cover element (8) between the open position and the closed position below a second speed (n ₂ ) in which the fiber ring (5) has already collapsed due to the decreasing centrifugal forces, is sucked due to the restored negative pressure in the rotor housing (2). Open-end rotor spinning machine according to claim 6, characterized in that the control device (34) is designed to cancel the negative pressure to above the first speed (n ₁ ), the adjusting device (32) to control so that the cover element (8) displaced into the open position becomes. Open-end rotor spinning machine according to one of claims 6 or 7, characterized in that
a valve (31) for switching off the vacuum supply (10) is present and the control device (34) is designed to close the vacuum supply (10) above the first rotational speed (n ₁ ) to close the valve (31). Open-end rotor spinning machine according to one of claims 6 to 8, characterized
characterized in that the control device (34) is designed to control the adjusting device (32) such that the cover element (8) below the
second speed (n ₂ ) is transferred from the open position to the closed position with effective vacuum supply (10). Open-end rotor spinning machine according to one of claims 6 to 9, characterized in that the control device (34) is adapted to control the adjusting device (32) so that the cover element (8) below the second speed (n ₂ ) with effective vacuum supply ( 10) is transferred from the closed position to the open position.

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