EP3985151B1 - Spinning preparation machine - Google Patents

Description

The invention relates to a spinning preparation machine for mixing fibers, with a removal device for removing the fibers from the spinning preparation machine and with a filling device for filling the spinning preparation machine with fibers. The spinning preparation machine is designed as a shaft mixer with at least two mixing chambers, wherein the filling device has a fiber material inlet and a transport air outlet with a transport air outlet channel and a distribution channel guided from the fiber material inlet to the transport air outlet via the at least two mixing chambers.

In a fiber preparation plant in a spinning mill, delivered fibers or fiber flakes are prepared for use in a spinning machine. In a fiber preparation plant, the fibers to be prepared for spinning go through several processing stages. In a first stage, the fibers are separated from fiber bales in the form of fiber flakes. So-called bale openers are usually used for this. These fiber flakes are removed from the bale opener via a pneumatic flake conveyor and, for example, taken to a subsequent cleaning machine.

After the cleaning machine, the fiber flakes are usually conveyed into a mixer, which ensures that the fiber flakes are mixed through various shafts, for example. The fibers are then removed from the mixer using a removal device, for example using a needle-lattice cloth, and transported further. DE 37 13 5902 A1 discloses a mixer with several filling shafts. The filling shafts are filled simultaneously via the pneumatic transport system. By controlling the removal devices of the individual shafts, the fiber material is mixed thoroughly.

The EP 0 874 070 A1 a shaft mixer with several shafts. The fiber material is distributed to the various shafts or chambers of the mixer by means of a pneumatic conveyor with the help of transport air. The transport air is discharged from the chambers into an exhaust air duct via air-permeable side walls.

The shaft mixer is divided into various shafts, which are open at the top and are connected to the pneumatic conveyor line. The incoming fiber flakes are evenly distributed to the various shafts via a distributor. After the distributor, the shafts initially extend vertically before making a 90° bend, so that the shafts or their flake fillings now extend horizontally. Their horizontal extension ends in front of a ladder cloth, which passes all shafts, essentially in a vertical direction from bottom to top, and removes the fibers. By designing the mixer as a shaft mixer, the fibers are mixed thoroughly due to the different lengths of the shafts, i.e. the distances that the fibers have to travel, as the fibers fed to the mixer at different times and therefore from different bales are simultaneously removed from the different shafts by the removal device. This design of shaft mixers has proven itself.

The disadvantage of this design is that separating the fiber material from the transport air is complex. Each chamber or shaft is provided with an air-permeable wall, which also results in a multiple risk of blockages. During operation, the air permeability of the individual partition walls changes, which can lead to different filling of the shafts due to the pressure conditions, which must be corrected by appropriate control of the distribution.

Another spinning preparation machine for blending fibers is in DE 41 11 894 A1 revealed.

The object of the invention is therefore to create a device which provides a simple separation of fiber material and transport air and at the same time avoids a different influence of the various filling levels of the shafts of the mixer by a shaft-by-shaft separation of the transport air from the fibers.

The problem is solved by a device having the features of the independent claim. To solve the problem, a novel spinning preparation machine is for mixing fibers proposed with a removal device for removing the fibers from the spinning preparation machine and with a filling device for filling the spinning preparation machine with fibers. The spinning preparation machine is designed as a shaft mixer with at least two shafts, wherein the filling device has a fiber material inlet and a transport air outlet with a transport air outlet channel and a distribution channel led from the fiber material inlet to the transport air outlet via the at least two shafts. The distribution channel is separated from the transport air outlet by a perforated element. The perforated element is designed with a convex shape seen in the direction of the transport air outlet.

A transport channel is provided as a filling device through which the fiber material is brought into the distribution channel with transport air as a fiber-air mixture. The distribution channel is kept open towards the shafts. Due to the flow guided through the fiber material inlet, the transport air follows the distribution channel to the transport air outlet. The transport air outlet is arranged on a side opposite the fiber material inlet so that the fiber-air mixture passes over the shafts. The fibers or fiber flakes fall down into the shafts. At the end of the distribution channel, the perforated element is installed as a curved element to separate the fiber material from the transport air and thus separates the distribution channel from the transport air outlet channel. The transport air passes through the perforation into the transport air outlet channel while the fiber material is held back. The convex shape of the perforated element causes the fiber-air mixture to accelerate in the upper area of the distribution channel in front of the perforated element, which contributes to automatic cleaning of the perforated element. It has also been shown that the flows created in the distribution channel by the arrangement and shape of the perforated element, as well as the resulting pressure conditions in the individual shafts, are conducive to an even distribution of the incoming fibers into the shafts. The positioning of the transport air outlet channel or the fiber material inlet in relation to the machine's longitudinal axis is not important. The transport air outlet channel and the fiber material inlet can be provided either at the front or at the rear of the machine. This means that The machine can be ideally integrated into an existing fiber preparation plant in a spinning mill.

The fibers pass through the individual shafts and are mixed by a deflection and with the help of the removal device. The principle of first vertical and then horizontal flow through the shafts before they reach the removal device is known from the state of the art. For example, a needle slat cloth can be used as an ascending conveyor as the removal device, which on the one hand removes the fibers from the various shafts and on the other hand transports the removed fibers to a fiber material outlet.

The shafts are advantageously surrounded by airtight shaft walls. Because the separation of the transport air from the fibers is concentrated on the transition from the distribution channel to the transport air outlet channel and does not occur in an uncontrolled manner via individual shaft walls, it is possible to fill the shafts evenly under constant flow and pressure conditions.

It is also advantageous if the distribution channel is surrounded on at least three sides by air-tight channel walls. Attempts in earlier designs to separate part of the transport air to the side of the distribution channel according to the distance traveled have proven to be disruptive. This is also due to the fact that the fiber-air mixture is not homogeneous and the load of the transport air with fiber material is subject to constant fluctuations. The risk of clogging of the air-permeable elements is also minimized, in particular due to the predictable flow and pressure conditions with a central separation of transport air and fibers. Due to the prevailing flow conditions and the pressure conditions in the shafts, the shafts are filled evenly even without corresponding guide elements such as flaps or sheets in the distribution channel.

Preferably, the convex shape of the perforated element is formed from a series of flat sieve elements. As an alternative to a circularly arc-shaped perforated element, this is made by a series of flat sieve elements. The individual sieve elements are joined together in such a way that that an overall convex shape of the perforated element is created. The individual sieve elements have a corresponding perforation and are connected to one another, for example, by welding, gluing or screwing. In an alternative production method, the perforated element can be formed from a flat sheet of metal using a corresponding bending process or by forming bending edges between the sieve elements. The bending edges are to be viewed as the boundary of the individual sieve elements. In this way, the production of the perforated element can be simplified compared to production by rolling a sheet of metal to a large diameter and is more cost-effective. The narrower the individual sieve elements are, the more the shape of the joined or connected sieve elements approaches a circular arc segment. A segment-by-segment construction of the convex perforated element has no decisive influence on the functioning of the perforated element or the flow conditions, provided the perforated element is made up of more than three sieve elements.

The convex shape preferably corresponds to a circular arc with a radius in a range from 200 mm to 1,000 mm, particularly preferably in a range from 400 mm to 800 mm. The size of the radius to be selected depends on the size of the spinning preparation machine. Such a design of the perforated element leads to advantageous flow conditions, which prevents fibers from becoming stuck in the perforation. In order to achieve good air permeability and to avoid excessive back pressure, the perforated element preferably has a perforation of 20% to 50%. This means that at least 20%, but not more than 50% of the surface is perforated, i.e. there is between 0.2 cm ² and 0.5 cm ² of free passage in the perforated element per cm ² of area. Too much perforation would result in good fibers passing through the holes or becoming caught in the holes and causing snags.

Advantageously, the perforated element is divided into at least two areas, wherein the areas have different perforations. For example, an upper half of the perforated element with a perforation of 28% and a lower Half of the perforated element is designed with a perforation of 21%. Due to the resulting flow conditions, the differential pressure can be evened out across the perforated element and the transport air is separated more evenly across the cross section of the perforated element. This type of design of the perforated element is facilitated by a construction with sieve elements arranged in a row. More than two areas with different perforations are also conceivable. The individual sieve elements can easily be provided with different perforations.

It is advantageous if the convex perforated element extends over an angle of more than 90 degrees. This increases the screen surface and also improves the flow conditions. The flow conditions in front of the perforated element are also influenced in such a way that no or only a small amount of transport air is diverted from the distribution channel through the convex shape of the perforated element into the last shaft in front of the perforated element.

In a further development of the invention, a cover element for setting a negative pressure in the transport air outlet channel is provided on a side of the perforated element facing the transport air outlet. The cover element can be designed as a filter cloth or as a cover plate. By selectively partially covering the perforation of the perforated element, the pressure and flow conditions on the perforated element are influenced and a desired differential pressure can be set across the perforated element. This also evens out the air flow through the perforated element. At the same time, the escaping transport air is kept free of large amounts of dust or fiber particles when a filter cloth is used.

Advantageously, the perforation in the perforated element is formed by round or square openings with a cross-section of less than 0.1 cm ^2. The small cross-sectional size of the individual openings of the perforation prevents or at least It is strongly restricted that good fibres pass through the perforated element into the transport air outlet channel.

Preferably, the perforated element is made of metal. Alternatively, the perforated element is made of plastic. If the perforated element is made of metal, a small thickness, for example less than 1 mm, can be selected, which in turn leads to better cleaning by the flow passing over the perforated element due to the low edge height of the passages. However, if the shaft mixer is smaller, a perforated element made of plastic with sufficiently high stability and strength can also be used.

Preferably, an air guide element is provided in the distribution channel above a shaft partition between two shafts. The air guide element is designed as the upper end of the shaft partition. The air guide element briefly accelerates the flow from the fiber material inlet to the transport air outlet, which leads to an improvement in the distribution of the fiber material to the shafts. The air guide element is advantageously provided with a convex end in its shape against the distribution channel in order to prevent fibers from sticking.

It is advantageous if the transport air outlet channel has a larger cross-section than the perforated element. The transport air outlet channel is arranged in the shape of a hood around the perforated element at a certain distance. The distance between a wall of the transport air outlet channel and the perforated element is preferably greater than 100 mm. This calms the flow and promotes a more even passage of the transport air through the perforated element. Furthermore, a maintenance opening is preferably provided in the transport air outlet channel in order to be able to check the condition of the perforated element and, if necessary, to clean the transport air outlet channel. At least part of the maintenance opening is advantageously designed to be transparent.

In an alternative to the hood-shaped design of the transport air outlet channel, the transport air outlet channel advantageously has a first section and a second section adjoining the first section, with the first section being guided along the perforated element and the second section being guided away from the perforated element. The first section of the transport air outlet channel is adapted in its design to the convex perforated element so that an arc-shaped channel is created. The transport air flowing through the perforated element into the first section of the transport air outlet channel is subsequently diverted and guided along the perforated element and reaches the second section of the transport air outlet channel at the end of the perforated element.

Particularly preferably, the first section and the second section of the transport air outlet channel are designed in their cross-section such that the transport air reaches a minimum speed of 12 m/s. The value for the speed of the transport air in the transport air outlet channel is selected such that the dust that accumulates and the fiber residues that enter the transport air outlet channel through the perforation are entrained by the transport air. This can prevent an accumulation of dust and fiber residues in the transport air outlet channel. For inspection and any necessary cleaning of the transport air outlet channel, a maintenance opening is preferably provided between the first section and the second section.

Figur 1

eine schematische Darstellung einer Spinnereivorbereitungsmaschine;

Figur 2

eine schematische Darstellung eines Schnittes an der Stelle X-X nach Figur 1;

Figur 3

eine erste Ausführung eines perforierten Elements;

Figur 4

eine zweite Ausführung eines perforierten Elements und

Figur 5

eine schematische Darstellung eines Querschnitts einer weiteren Ausführung des Transportluftaustrittskanals.

In the following, the invention is explained using an exemplary embodiment and explained in more detail by drawings.

Figure 1

a schematic representation of a spinning preparation machine;

Figure 2

a schematic representation of a section at point XX according to Figure 1 ;

Figure 3

a first embodiment of a perforated element;

Figure 4

a second embodiment of a perforated element and

Figure 5

a schematic representation of a cross-section of another embodiment of the transport air outlet duct.

Figure 1 shows a schematic representation of a spinning preparation machine 1 according to the invention and Figure 2 a schematic representation of a section at point XX according to Figure 1 . Shown is a spinning preparation machine 1 in the design of a shaft mixer with four shafts 2 to 5. The individual shafts 2 to 5 are separated from one another by shaft partitions 17 to 19, with the separation being provided over the entire width B, but not over the entire height H of the shaft mixer. The shafts 2 to 5 are provided as shafts 2 to 5 that are open at the top and bottom and are delimited on four sides. For example, the shaft 4 is delimited by the shaft partitions 17 and 18 and the shaft outer walls 19 and 20. At the lower end of each shaft partition 17 to 19, a shaft partition end piece 20 is provided which directly connects to the shaft partition 17 to 19. The shaft partition end piece 20 serves to redirect the fiber flow which slides downwards through the shafts 2 to 5 from a vertical to a horizontal movement.

The fiber material is introduced into the spinning preparation machine 1 in the form of a fiber-air mixture 7 through the fiber material inlet 6 with the aid of transport air 10 and is guided through a distribution channel 11 via the shafts 2 to 5 to the transport air outlet channel 9. The distribution channel 11 is limited on three sides by an upper distribution channel wall 14 and two lateral distribution channel walls 15 and 16. The distribution channel 11 is open opposite the shafts 2 to 5. In Figure 1 this demarcation of the distribution channel 11 is shown with the channel course 12 as an auxiliary line. A perforated element 13 is inserted in the transition from the distribution channel 11 to the transport air outlet channel 9. The perforated element 13 separates the distribution channel 9 from the transport air outlet channel 9. This separates the transport air 10 from the fiber material. The perforated element 13 has a convex shape with a radius R when viewed in the direction from the fiber material inlet 6 to the transport air outlet 8. To improve the flow in the distribution channel 11, air guide elements 21 are mounted above the shaft partition walls 17 to 19.

The transport air 10 is discharged from the transport air outlet channel 9 via the transport air outlet 8. The transport air outlet channel 9 is designed in such a way that it hood-shaped around the perforated element 13 and is arranged with its walls at a distance A from the perforated element 13. This shape enables the transport air 10 to pass unhindered through the perforated element 13.

The fiber material is mixed by the deflection of the fiber material in the individual shafts 2 to 5 and the subsequent horizontal transport with the aid of the conveyor belt 24 to the removal device 25 as well as the in turn rising transport within the removal device 25. The removal device 25 in the embodiment shown is formed by a rising slat cloth and a discharge roller. The mixed fiber material is transferred from the removal device 25 into an outlet channel 26 which leads to the fiber material outlet 27.

Figure 3 shows a first embodiment of a perforated element 13 which is composed of a plurality of individual sieve elements 28. The sieve elements 28 are designed as flat sieve surfaces provided with a perforation 30. The perforation 30 is in Figure 3 shown schematically and extends evenly over all sieve elements 28 of the perforated element 13. The sieve elements 28 are arranged one behind the other in such a way that a convex element 13 is formed in a circular arc with a radius R.

Figure 4 shows a second embodiment of a perforated element 13 which is also composed of individual sieve elements 28 arranged one behind the other. The perforated element 13 is divided into two areas 29 and 31, whereby a first area 29 is designed with a perforation 30 which differs from the perforation 32 in the second area 31. The perforation 30 in the first area 29 is larger than the perforation 32 in the second area 31. This results in a more even flow through the perforated element 13 over its entire length. The perforations 30 and 32 are in Figure 4 shown schematically and extend evenly over the corresponding sieve elements 28 of the areas 29 and 31 of the perforated element 13. Furthermore, the convex perforated element 13 extends over an angle α of more than 90 degrees. Due to the increased arc length of more than 90 degrees results in a better discharge of the transport air through the perforated element 13.

Figure 5 shows a schematic representation of a cross section of another embodiment of the transport air outlet channel 9. The perforated element 13 is shown as a circular arc with a radius R and an angle α of more than 90 degrees. In contrast to the hood-shaped design of the transport air outlet channel 9 as shown in Figure 1 As shown, the transport air outlet channel 9 consists of Figure 5 from a first section 35 which is arranged behind the perforated element 13 and a second section 36 following the first section 35 which brings the transport air 10 to the transport air outlet 8. Arrows show the flow 33 of the transport air 10 guided through the perforated element 13 into a first section 35 of the transport air outlet channel 9 and from the first section 35 into the second section 36. The transport air outlet 8 is shown as a flange by way of example. A maintenance opening 34 is shown between the sections 35 and 36 of the transport air outlet channel 9.

The present invention is not limited to the embodiments shown and described. Modifications within the scope of the patent claims are possible, as is a combination of the features, even if these are shown and described in different embodiments.

legend

1

Spinning preparation machine

2 - 5

Shaft

6

Fibre entry

7

Fibre-air mixture

8

Transport air outlet

9

Transport air outlet duct

10

Transport air

11

Distribution channel

12

Channel course

13

Perforated element

14

Upper distribution channel wall

15 - 16

Lateral distribution channel wall

17 - 19

Shaft partition wall

20

Shaft partition end piece

21 - 22

Shaft outer wall

23

Air guide element

24

Conveyor belt

25

Removal device

26

Outlet channel

27

Fibre material discharge

28

Sieve element

29

First area

30

Perforation first area

31

Second area

32

Perforation second area

33

flow

34

Maintenance opening

35

First section transport air outlet duct

36

Second section transport air outlet duct

A

Distance

B

Width

H

Total height

R

radius

α

angle

Claims (15)

1. Spinning preparation machine (1) for mixing fibers, comprising a removal device (25) for removing the fibers from the spinning preparation machine (1) and a filling device for filling the spinning preparation machine (1) with fibers, wherein the spinning preparation machine (1) is designed as a chute mixer having at least two chutes (2-5), wherein the filling device has a fiber material inlet (6) and a transport air outlet (8) having a transport air outlet duct (9) and a distribution duct (11) leading from the fiber material inlet (6) to the transport air outlet (8) via the at least two chutes (2-5), characterized in that the distribution duct (11) is separated from the transport air outlet (8) by a perforated element (12), the perforated element (12) being designed to have a convex shape when viewed in the direction of the transport air outlet (8).
2. Spinning preparation machine (1) according to claim 1, characterized in that the chutes (2-5) are surrounded by air-impermeable chute walls (17-20).
3. Spinning preparation machine (1) according to either claim 1 or claim 2, characterized in that the distribution duct (11) is surrounded on at least three sides by air-impermeable duct walls (14, 15, 16).
4. Spinning preparation machine (1) according to at least one of the preceding claims, characterized in that the convex shape of the perforated element (13) is formed from flat sieve elements (28) lined up in a row.
5. Spinning preparation machine (1) according to at least one of the preceding claims, characterized in that the convex shape of the perforated element (13) corresponds to an arc of a circle with a radius (R) in a range from 200 mm to 1000 mm.
6. Spinning preparation machine (1) according to at least one of the preceding claims, characterized in that the perforated element (13) has a perforation of 20% to 50%.
7. Spinning preparation machine (1) according to at least one of the preceding claims, characterized in that the perforated element (13) is divided into at least two regions (29, 31), the regions (29, 31) having different perforations (30, 32).
8. Spinning preparation machine (1) according to at least one of the preceding claims, characterized in that the convex perforated element (13) extends over an angle (α) of more than 90 degrees.
9. Spinning preparation machine (1) according to at least one of the preceding claims, characterized in that a cover element for setting a negative pressure in the transport air outlet duct (9) is provided on a side of the perforated element (13) facing the transport air outlet (8).
10. Spinning preparation machine (1) according to at least one of the preceding claims, characterized in that the perforation in the perforated element (13) is formed by round or angular openings with a cross section of less than 0.1 cm².
11. Spinning preparation machine (1) according to at least one of the preceding claims, characterized in that the perforated element (13) is made of metal.
12. Spinning preparation machine (1) according to at least one of the preceding claims, characterized in that the perforated element (13) is made of plastics material.
13. Spinning preparation machine (1) according to at least one of the preceding claims, characterized in that an air guide element (21) is provided in the distribution duct (11) above a chute partition wall (17, 18) between two chutes (4, 5).
14. Spinning preparation machine (1) according to at least one of the preceding claims, characterized in that the transport air outlet duct (9) has a first portion (35) and a second portion (36) adjoining the first portion (35), the first portion (35) being guided along the perforated element (13) and the second portion (36) being guided away from the perforated element (13).
15. Spinning preparation machine (1) according to at least one of the preceding claims, characterized in that the transport air outlet duct (9) is designed in such a way that the transport air (10) reaches a minimum speed of 12 m/s.

Images