GB2140048A

GB2140048A - Feeding textile fibres in open- end spinning units

Info

Publication number: GB2140048A
Application number: GB08411378A
Authority: GB
Inventors: Frantisek Ferkl; Oldrich Tesar; Ladislav Civrny; Jaroslav Dykast
Original assignee: Vyzkumny Ustav Bavlnarsky AS
Current assignee: Vyzkumny Ustav Bavlnarsky AS
Priority date: 1983-05-20
Filing date: 1984-05-03
Publication date: 1984-11-21
Also published as: DE3417567C2; GB8411378D0; GB2140048B; CS238155B1; DE3417567A1; IT8420694A0; IT1209537B

Abstract

An object of the invention is to avoid the escape of separated fibres into the space between the front face of the opening roller (2) and the housing (8) by an additional air flow and to direct the fibres (41) by means of said flow into the supply duct (14) provided in the housing (1) of an open-end spinning unit. The additional air flow is introduced through an additional air intake (9) provided in the cover (8) of the housing (1) and directed into the space defined by a part of the front face of the opening roller (2), the active surface thereof and by the opposite peripheral wall of the cavity (10) of the housing (1). <IMAGE>

Description

SPECIFICATION Separating textile fibres in open-end spinning units This invention relates to separating fibres in an open-end rotor spinning unit consisting substantially of two parts, viz. a spinning rotor housing accomodating a spinning rotor, and a fibre separation housing in the cavity of which is received a feed roller and a high-speed rotary separating cylinder which is associated with said feed roller and designed for separating fibres from a supplied fibrous material.

The separated or discrete fibres are transported through a supply duct to a spinning rotor accommodated in the spinning rotor housing where they are converted into yarn.

One of the essential conditions of a spinning process is a minimum thread breakage rate and consequently low claims on machine attendance.

The thread breakage rate is influenced, to a considerable extent, by the fibre separating process and the following process of taking fibres off the active surface of the separating cylinder. A well-known shortcoming of these two processes is caused by choking of the separating cylinder with fibres, which, in extreme cases, may lead to the interruption of spinning process, due to the cylinder blocking. The cause can be seen, on the one hand, in an insufficient, or delayed fibre take-off, since some of the fibres remain in a sawtooth or needle clothing constituting the active surface of the separating cylinder and, on the other hand, in the escape of discrete fibres into the space between the front face of the separating cylinder and the opposite wall of the cover which closes the cavity in the separation housing.Such a fibre escape is moreover promoted by a helical configuration of the cylinder clothing which, due to its lead, lifts the revolving fibres outside the take-off zone into the space above the front face of the separating cylinder where they form clusters which cause an unwanted braking of the cylinder up to the stoppage thereof in extreme cases. In the spinning process in which yarns are taken off at a relatively high speed and in which the spinning rotors have to be supplied with large amounts of discrete fibres, this problem becomes more serious.

The problem of choking the separating cylinder has been coped with by various measures, such as. for instance, by depressions, projections or spirals on the front face of the separating cylinder, which all are designed for whirling air in the space between said front face and the opposite wall of the cover and thus to prevent the flying fibres from depositing.

Another measure consists in sucking in technological air through the separating cylinder, or, alternatively, also through a part of its front face (U.S.P. NO. 3,922,839).

Czechoslovak Inventor's Certificate No.

164,384 discloses a method wherein air is supplied through a distribution chamber via holes which open, among others, also on the front face of the separating cylinder.

A A common drawback of all the afore-men- tioned measures is in that they are rather to remedy the damages caused by the fibre flyoff in the fibre separating and taking-off process than to prevent such damages.

It is an object of the present invention to prevent the separated fibres from escaping into the space above the front face of the separating cylinder and consequently to improve the conditions of the fibre separating and taking-off process in the open-end spinning unit.

One aspect of the invention provides a method of separating textile fibres supplied to a rotary separating cylinder in a cavity of a separation housing of open-end spinning unit, of taking the separated fibres off the active surface of said separating cylinder, and of transporting the separated fibres into a fibre supply duct wherein the separated fibres and the fibres which have escaped from the separation process are exposed, in the fibre take-off and transport zone, or downstream of said zone, to an additional air flow which is introduced into a space defined by a part of the front face of the separating cylinder, the active surface thereof and by the opposite peripheral wall of the cavity of the separation housing, in order to direct the fibres under the plane of the front face of the separating cylinder.

The method enables the fibres which during the separation process have been brought into the space above the plane of the front face of the separating cylinder and which, in the takeoff zone or downstream thereof, have entered the space between the front face of the separating cylinder and the cover of the separation housing, to be returned by the additional air flow back under the plane of said front face of the separating cylinder. Due to a specific arrangement of the additional air intake in the fibre take-off zone or downstream thereof, both the escaped and the lately taken-off fibres are returned into the clothing of the separating cylinder and, after the next revolution thereof, duly taken off and delivered into the supply duct.

For directing the additional airflow into the fibre take-off zone, it is also advantageous that the separated fibres and the fibres escaped from the separation process are exposed in the take-off and transport zone to the additional air flow which is at least partially parallel to the direction of fibre transport into the supply duct.

Another aspect of the invention provides an open-end spinning unit comprising a separation housing with a cavity which accommo dates a rotary fibre separating cylinder with an active surface and which is closed by a cover, a feed roller associated with said separating cylinder and serving for supplying a fibrous material, and a supply duct for transporting separated fibres into a spinning rotor wherein in the cover of the separation housing there is provided an additional air intake for introducing an additional air flow into a space defined by a part of the front face of the separating cylinder, the active surface thereof and the opposite peripheral wall of the cavity of the separation housing.

A preferred embodiment of supplying the additional air flow to the above-described space consists in that the additional air intake provided in the cover of the separation housing extends in parallel to the axis of the fibre separating cylinder.

For improving the conditions of taking off discrete fibres by introducing the additional air flow at least partially in the direction of fibre transport through the supply duct, it is also advantageous that the additional air intake provided in the cover of the separation housing extends askew to the axis of the fibre separating cylinder.

For the production of additional air flow in the additional air intake communicating with the ambient atmosphere, it is possible to utilize the suction produced by a subatmospheric pressure in the spinning rotor, said subatmospheric pressure being necessary for taking off and transporting separated fibres through the supply duct in the separation housing.

Some preferred embodiments of the invention will be described by way of example with reference to the accompanying schematic drawings, in which: Fig. 1 is a sectional view of an open-end spinning unit, showing an additional air intake disposed downstream of the fibre take-off zone in the fibre separation housing; Fig. 2 is a fragmentary sectional view showing the additional air intake extending in parallel to the fibre separating cylinder axis; Fig. 3 is a fragmentary sectional view showing the additional air intake extending askew to the fibre separating cylinder axis; and Fig. 4 is a sectional view of an open-end spinning unit, showing an additional air intake facing directly the fibre take-off zone in the fibre separation housing.

As can be seen in the drawings, and particularly Figure 1 thereof, an open-end spinning unit consists of a fibre separation housing 1 and a spinning rotor housing 62, both said elements being coupled with each other in the operationai position. The fibre separation housing 1 is provided with a cavity 10 accommodating a rotary fibre separating cylinder 2 the active surface 21 of which is provided with a sawtooth or needle clothing. The separating cylinder 2 is associated with a feeding mechanism comprising a feed roller 3, a shoe 31 and a condenser 32 and serving for feeding textile material in the form of a fibrous sliver 4 to said cylinder 2. The shoe 31 which is forced to wash the feed roller 3 by a spring 34, forms an integral unit with the condenser 32, said unit being journalled about a pivot 33 fixed in the wall of the housing 1.The feeding mechanism is accommodated in an inlet space 11 of the housing 1 which space communicates with the cavity 1 0. The latter further communicates via cleaning gap 12, impurity withdrawing duct 1 3 and pipe 51 with a central conduit 5 for withdrawing impurities 42. The cavity 10 opens into a fibre supply duct 14 for feeding separated or discrete fibres 41 to a spinning rotor 6 the shaft 60 of which is mounted in bearings 61 secured in the spinning rotor housing 62. The housing 62 is suspended on the frame 7 of an open-end rotor spinning machine (not shown). In the shown embodiment the spinning rotor 6 is provided with ventilation ports 63 for producing a sub-atmospheric pressure.

The thus sucked-in air is withdrawn out of the interior 64 of the spinning rotor housing 62 through an outlet 65 into a central air channel 66. The shaft 60 of the spinning rotor 6 is driven by a driving belt 67.

The cavity 10 of the separation housing 1 is closed by a stationary cover 8 which is provided with an additional air intake 9 through which an additional air flow 91 is supplied.

In operation, the fibrous sliver 4 is supplied through the condenser 32 to the feed roller 3, forced there to wash by the shoe 31 and delivered to the fibre separating cylinder 2.

The active surface 21 of said cylinder 2 is provided by e.g. sawtooth clothing by which individual fibres 41 are combed out of the sliver fringe. Discrete fibres 41 are then taken off the clothing and fed through the supply duct 14 to the spinning rotor 6 where they are converted in a known way into yarn.

Impurities 42 which are released from the fibrous material during the separation process are ejected by centrifugal force into the cleaning gap 1 2 and withdrawn via duct 1 3 and pipe 51 into the central conduit 5.

In the fibre separating process, some discrete fibres 41 tend to escape into the space above the front face 22 of the separating cylinder 2, due to a helical arrangement of its clothing. According to the invention, such fibres are blown back to the active surface 21 of the separating cylinder 2 by the additional air flow sucked in through the additional air intake 9.

In the embodiment shown in Fig. 3, the additional air intake 9 extends askew to the axis of the separating cylinder 2 so as to direct the escaped fibres 41, at least partially, in parallel to the transport thereof into the supply duct 14 and to prevent them from penetrating into the space between the front face 22 of the separating cylinder and the cover 8. In this way, the conditions of the fibre separating process are also improved.

Simultaneously, the additional air flow 91 positively influences the fibres which fail to have been taken off in the take-off zone. By arranging the additional air intake 9 downstream of this zone, the additional air flow 91 prevents an unwanted escape of such fibres to the space above the front face 22 of the separating cylinder so that after the next revolution thereof about the cylinder 2 they are duly taken off.

By directing such an additional air intake into one of the afore-mentioned zones it is made possible to prevent the fly-off fibres from accumulating above the front face of the separating cylinder and to improve thus the conditions of fibre separation, take-off and transport whereby not only the actual spinning process but also the quality of final yarn product are positively influenced.

Claims

1. A method of separating textile fibres supplied to a rotary separating cylinder in a cavity of a separation housing of open-end spinning unit, of taking the separated fibres off the active surface of said separating cylinder, and of transporting the separated fibres into a fibre supply duct, wherein the separated fibres and the fibres which have escaped from the separation process are exposed, in the fibre take-off and transport zone, or downstream of said zone, to an additional air flow which is introduced into a space deffined by a part of the front face of the separating cylinder, the active surface thereof and by the opposite peripheral wall of the cavity of the separation housing, in order to direct the fibres under the plane of the front face of the separating cylinder.

2. A method as claimed in claim 1, wherein the separated fibres and the fibres which have escaped from the separation process are exposed in the take-off and transport zone to the additional air flow which is at least partially parallel to the direction of fibre transport into the supply duct.

3. An open-end spinning unit comprising a separation housing with a cavity which accommodates a rotary fibre separating cylinder with an active surface and which is closed by a cover, a feed roller associated with said separating cylinder and serving for supplying a fibrous material, and a supply duct for transporting separated fibres into a spinning rotor wherein in the cover of the separation housing there is provided an additional air intake for introducing an additional air flow into a space defined by a part of the front face of the separating cylinder, the active surface thereof and the opposite peripheral wall of the cavity of the separation housing.

4. A unit as claimed in claim 3, wherein the additional air intake provided in the cover of the separation housing extends in parallel to the axis of the fibre separating cylinder.

5. A unit as claimed in claim 3, wherein the additional air intake provided in the cover of the separation housing extends askew to the axis of the fibre separating cylinder.

6. A method of separating textile fibres supplied to a rotary separating cylinder in a cavity of a separation housing of open-end spinning unit, of taking the separated fibres off the active surface of said separating cylinder, and of transporting the separated fibres into a fibre supply duct, substantially as here it before described with reference to the accompanying drawings.

7. An open-end spinning unit substantially as hereinbefore described with reference to Figs. 1 and 2 of the accompanying drawings.

8. An open-end spinning unit substantially as hereinbefore described with reference to Figs. 1 and 3 of the accompanying drawings.

9. An open-end spinning unit substantially as hereinbefore described with reference to Fig. 4 of the accompanying drawings.