|Title of Invention||
CLEANING DEVICE FOR FIBRE FLOCKS
|Abstract||The invention relates to a cleaning device for fibre flocks, in particular made of cotton, comprising a horizontal roller fitted with beater elements, an inlet being arranged above its upper side at one end of the roller and an outlet for the delivery stream being arranged at the other end, and transfer chambers defined by deflecting plates positioned at an angle to the roller axis are arranged between the inlet opening and the outlet opening for the delivery stream which rotates about the roller axis. By providing an air separating device in front of the inlet opening, the fibre flock stream can be compressed, so that the cleaning device brings about better cleaning with increased production. Fig. 2|
CLEANING DEVICE FOR FIBRE FLOCKS
The invention relates to a cleaning device for fibre flocks, in particular made of cotton, comprising a horizontal roller fitted with beater elements, an inlet being arranged above its upper side at one end of the roller and an outlet for the delivery stream being arranged at the other end, and transfer chambers defined by deflecting plates positioned at an angle to the roller axis are arranged between the inlet opening and the outlet opening for the delivery stream which rotates about the roller axis.
At least one such cleaning device is known and available on the market. It serves the purpose of opening the fibre flocks supplied in the delivery air stream and removing impurities therefrom. The fibre material is supplied together with transfer air via the inlet to an axial end of the roller. The air-flock stream is conveyed spirally around the roller whereby this is guided several times over the cleaning bar grates. The flocks are then gripped by the drum fitted with tines or beaters , brought over the cleaning bar grates and gradually brought to the other axial end of the opening roller by means of deflecting chambers to convey the opened fibre flocks through the outlet of the machine by means of centrifugal force. The flocks are also beaten by hitting against the walls defining the transfer chambers or deflecting chambers whereby impurities and dust can be largely separated from the fibre material.
EP 381860, EP 379726 and EP 447966 describe the cleaning device in detail. EP 381860 describes the use of deflector plates as separation between the individual transfer chambers which can improve the opening of the flocks. In addition, this document describes that in the cleaning device the inlet is arranged such that the delivery air stream which transports the fibre flocks and enters through the inlet runs approximately tangentially to the opening roller from top to bottom and specifically in such a manner that the delivery stream has the same direction of motion as the circumference of the rotating roller at the point where it impinges upon the roller circumference. In this case, the beating pins of the roller should not move in the opposite direction to the incoming delivery air stream.
EP 379 726 describes the integration of an additional dust-removing function in tne cleaning device. The dust-laden transfer air can be partly removed by suction through a perforated sheet in the area of the transfer chambers of the device. EP 447966 describes an alternative solution for the dust-removal function. In this case, the suction point is not located above the roller in the transfer chambers but before the bar grate arrangement. When viewed in the conveying direction of the textile fibres, a substantially perpendicular air- and dust-permeable wall is provided, which is part of a low pressure chamber to which a suction pipe is connected.
The cleaning device with these improvements is used today in many spinning mills. However, the cleaning does not function optimally particularly with larger delivery streams. The entrained transfer air in the delivery stream impedes the mechanical cleaning process. At the inlet the transfer air prevents optimal acceptance of the flocks by the beating pins of the roller. Since transfer air also enters into the cleaner, cross-flows are formed over the width of the roller, impeding the desired spiral flow. In addition, flock material thereby enters into the outlet stream without coarse cleaning and the cleaning efficiency of the cleaning device is thereby reduced. An additional disadvantage is the formation of vorticity by the excess transfer air, particularly by the cross-flows. The vorticity causes neps and damage to the fibres.
It is thus the object of the present invention to provide a device which avoids the aforesaid disadvantages and in particular optimises the mechanical cleaning of the cleaning device described above.
The object is achieved by the features specified in claim 1. By providing an air separating device in front of the inlet opening of the cleaning device, the transfer air can be largely separated and the fibre flock stream is compacted. Substantially only the fibre flocks enter the cleaner. The influence of the transfer air is thereby eliminated. An air-permeable wall is preferably arranged in the air separating device so that air can escape.
The air separating device can be variously constructed, preferably the fibre flocks are not damaged and no vorticity or excessive friction is formed in the device. For example, the air separating device can consist of an inlet which is arranged in such a manner that the air flock stream is supplied to the cleaner via a perforated sheet, the height of the channel tapering in such a manner that the excess transfer air can escape via the perforated sheet and only the actual fibre flock stream is supplied to the cleaner. As a result of the tapering, the delivery air is gently pressed from the flock material and only very little air still remains in the flock material. The feed channel is formed in such a manner that the material stream in the air separating device brushes past the perforated sheet.
The perforated sheet is preferably arranged in the transport direction of the material stream so that the material stream flows over the surface of the screen. The screen is preferably arranged in an interlocked manner in the material stream, the space behind the screen being larger and the space of the material stream in the direction of flow being smaller, so that the air can escape better. The perforated sheet is preferably designed so that no fibres adhere or are thereby damaged. The perforated sheet is possibly adjustable so that the air separation can be adapted to the delivery volume, for example, a larger tapering for a smaller fibre volume flow. A possible adjustment for the air permeability of the wall could also be provided.
Preferably a slight negative pressure is provided on the air outlet side of the air separating device. However, this should primarily remove the escaping air and not suck the active air from the fibre flock stream. The inventive idea lies in using mechanical air separation, for example, by squeezing out the air so that the required suction capacity and the maintenance of the entire machine is minimal.
An additional advantage is that dust is removed at the same time.
In particular, the end of the inlet can be configured so that the beating elements, for example, beating pins or tines, of the roller engage directly in the fibre flock stream
and entrain the flocks. The air stream generated by the rapid rotation of the roller win also positively influence the acceptance of the fibre flocks.
The outlet channel is preferably arranged tangentially away from the roller in such a manner that the fibre flock material is hurled by the roller in the direction of removal. The actual further transport after the cleaner is again taken over by the pneumatic transport system, in particular, a downstream fan can provide the necessary acceleration. In order to prevent the suction of the pneumatic system influencing the mechanical functioning of the cleaner, means are provided in the outlet channel of the cleaner to be able to introduce air into the fibre flock stream again. This can be achieved, among other things, passively by providing infiltrated air slits in the outlet channel. The pneumatic transport will then take up the required amount of air during suction of the fibre flock stream via these slits. Instead of slits, adjustable flaps or a grate can also be provided. These means are preferably self-adjusting depending on the flow rate.
The cleaning efficiency of the cleaning device can be observed by measuring the input and/or output streams, for example, by measuring the pressure or pressure differences in the line, the volume flow or the colour difference of the material, possibly combined with measurements at the separated material, the waste material. The measured values can additionally be used for regulation and control of the device, for example, for adjusting the amount of air to be separated in the air separating device, the throughput through the cleaner, the angle of adjustment of the cleaning bar grates or the volume of air supplied to the outlet again. By adjusting the separated amount of air, it is possible to adjust, for example, the degree of cleaning and/or the amount of waste and/or the throughput.
By separating the air stream from the material stream at the inlet, it is possible to have only two transfer chambers per pass in the cleaning device without any deterioration in 1 the quality of the cleaning. The number of passes required for the cleaning can also be reduced. For the same diameter and the same length of the roller, the passes thus
become broader, allowing a higher throughput. For example, from previously seven passes with seven deflector plates and three chambers, it is possible to go back to five passes with five deflector plates and two chambers for the same width of roller. The production capacity is thereby increased with the same cleaning quality and the same degree of opening. The chambers and the deflector element together with the actual air generation of the roller ensure that the actual passes of the material are in the optimal spiral form over the width of the roller between the inlet and the outlet. Cross-flows can no longer be formed so that each of the supplied fibre flocks covers the desired cleaning path and is sufficiently cleaned. In addition, the formation of vorticity and the associated nep formation and material damage is reduced.
The cleaning intensity is dependent on the speed of the roller and is no longer negatively influenced by the transfer air. The adjustment of the amount of waste by adjusting the angle of the bar grates is only determined by the actual speed of the roller and the volume flow of the fibres.
The internal dust separating function such as is provided in the present-day cleaning device can preferably be retained. The residual air released by the mechanical process in the cleaner is sufficient for the dust removal. Exemplary embodiments of the cleaning machine according to the invention are explained in detail hereinafter with reference to the drawings. The reference numerals are kept the same for all the drawings. In the figures:
Fig. 1 is a schematic drawing of a cleaning machine from the prior art;
Fig. 2 is a schematic cross-section through a cleaning machine according to
Fig. 3 is a schematic detailed drawing of the upper part of the machine with the
inlet channel and outlet channel according to the invention.
The cleaning machine according to the prior art is explained with reference to Figure 1, see also EP 381860, EP 379726 and EP 447966 where similar machines have
been disclosed with more detail and which form an integral part of this application. The cleaning machine shown in Fig. 1 has an opening roller 3 which is mounted in a housing to rotate about a horizontal axis and the periphery of which is usually fitted with beater elements 5, for example, beating pins or tines. In operation, the roller 3 is turned in the direction of the arrow by a drive motor not shown. Cleaning bar grates 4 are located below the underside of the roller 3.
The upper side of the roller 3 is covered at a distance from the roller periphery by a wall of which one horizontal middle section and two side sections inclined at about 45° and laterally adjacent thereto are provided, and a substantially vertical wall 9 adjacent to said wall, which is permeable to dust is also provided. The three wall sections are arranged in a terrace manner, that is in cross-section approximately like three sides of an equilateral trapezium, and respectively two wall sections enclose an angle a of about 135° with one another. The wall 9 is an example of the additional dust-removal function, configured in Figure 1 with the aid of a perforated sheet provided with holes about 1.5 mm in diameter but it can also be formed by a screen.
An inlet 1 opens from the top at one axial end of the roller 3 and an outlet 2 opens at the other axial end above the roller 3. Located between the openings of the inlet 1 and the outlet 2 on the upper side of the roller 1 are deflector plates 12 positioned obliquely to the axis of the roller 1 (only one deflector plate is visible in Figure 2), which define the transfer chambers between the upper side of the roller 1 and the upper casing wall. The entire area of the air- and dust-permeable wall 9 is part of a low pressure chamber to which a suction pipe is connected (both not shown).
In operation, the textile fibres in the form of flocks, which are to be cleaned and opened, are fed by a current of delivery air to the cleaning device through the inlet 1. The delivery air with the fibre flocks flows substantially at first around the underside of the rotating roller 3, then through the transfer chamber between the deflectors 12, which moves the air axially further in the direction of the axis of the roller 3, then again around the underside of the roller 1, then through the transfer chamber between the
deflector plates and again around the underside of the roller 1, in order to leave the machine finally through the outlet opening 10. The delivery stream moves in a substantially spiral shape which is indicated by the arrow 7. During the circulation around the underside of the roller 1, the fibre flocks are processed through the beater elements 3 and increasingly opened, and impurities are separated from the fibres. The coarser impurities, as for example, portions of shell, are removed between the bar grates 4 and collected in the space under the bar grates, for example, in a waste container 6 and are periodically sucked out by means of a suction device, which is not shown. The waste removal process can take place, for example, as shown in Figure 1 by means of a centrifugal roller 6. The waste space is hereby separated from the transfer air for the waste in the line. This does not influence the waste material separation at the grate.
The fibre flocks fly upwards into the next transfer chamber where they are further opened and turned around by impacting on the top wall. Fine, dust-like impurities, which have been separated from the fibres, can only be partially sucked out through the bar grates 4 whilst a large part of the dust remains in the delivery air stream. The air- and dust-permeable wall 9, the low pressure chamber and the suction pipe also serve the purpose of separating these fine impurities from the delivery air stream so that they cannot finally emerge through the outlet 2 with the fibres. The suction pipe is connected to a low pressure source or suction device, which is not shown, which sucks out the dust laden air through the wall 9.
The magnitude of the low pressure produced in the low pressure chamber or the amount of air sucked out through the wall 9 is adjustable, for example, by adjusting the low pressure source or the suction source or by providing an adjustable throttling member arranged in the suction pipe, e.g. an adjustable throttle valve. The airflow is adjusted so that it is sufficient to suck out the dust through the pipe, so that the dust is not deposited on the underside of the low pressure chamber. In order to observe this, inspection windows are provided on an outer wall. It can also be expedient to arrange at least one scavenging air inlet in the low pressure chamber, through which
scavenging air from the surroundings can be sucked into the low pressure chamber. The scavenging air inlet likewise contains an adjustable throttling members, e.g., a throttle valve.
Figures 2 and 3 show the cleaning device as described previously comprising an inlet 16 and outlet channel 17 according to the invention. The inlet channel 16 contains an air separating device 18 according to the invention, consisting of an air-permeable wall 10 through which the delivery air stream can escape into the exhaust air channel 19. This wall is arranged parallel to the delivery stream. As shown in Figure 3, the end of this inlet is arranged in such a manner that the fibre flocks which up till then are substantially free from delivery air can be taken over directly from the inlet by the beater elements. Since no more delivery air is present, the acceptance of the flocks by the roller is substantially a mechanical transfer. However, the flock stream should not escape from the inlet channel in a highly compressed state but it should correspond more to a compacted stream of fibre flock. It is therefore advantageous if the cross-section b2 (Figure 3) of the inlet channel is adjustable compared to the cross-section b1, wherein b2 is larger than b1. In addition, it is advantageous if the cross-section of a2 is adjustable compared to a1, where a2 is smaller than a1. The contact area with the air-permeable wall preferably remains constant, possibly depending on the volume of fibre flocks in the delivery stream.
1. A cleaning device for fibre flocks, in particular made of cotton, transported in a delivery air stream, comprising a horizontal roller fitted with beater elements, an inlet opening (1) being arranged above its upper side at one end of the roller and an outlet opening (2) for the delivery stream being arranged at the other end, characterised in that an air separating device (18) is arranged in front of the inlet opening (1), which separates the transfer air and the fibre flocks in such a manner that a compressed fibre flock stream is fed to the cleaner.
2. The cleaning device according to claim 1, characterised in that the air separating device (18) is a channel which tapers in the direction of the delivery stream and which has an air-permeable wall, whereby the transfer air can escape.
3. The cleaning device according to claim 2, characterised in that the air-permeable wall is arranged in the transport direction of the material stream.
4. The cleaning device according to claim 2 or 3, characterised in that the air-permeable wall is arranged in an interlocked manner in the material stream.
5. The cleaning device according to any one of claims 2 to 4, characterised in that an air removal channel is arranged at the air outlet side of the air-permeable wall.
6. The cleaning device according to claim 5, characterised in that the cross-section of the air removal channel is larger in the direction of the fibre stream.
7. The cleaning device according to claim 1 to 6, characterised in that a negative pressure is present in the air removal channel.
The cleaning device according to any one of the preceding claims, characterised in that the end of the inlet channel is arranged so that the fibre flocks are taken over directly by the beater elements of the roller.
The cleaning device according to any one of the preceding claims, characterised in that the amount of air to be separated can be adjusted.
The cleaning device according to any one of the preceding claims, characterised in that the air permeability of the wall can be adjusted.
The cleaning device according to any one of the preceding claims, characterised in that the outlet channel is arranged tangentially away from the roller.
The cleaning device according to any one of the preceding claims, characterised in that means are provided in the outlet channel to introduce air into the fibre flock stream.
The cleaning device according to claim 12, characterised in that the means are self-adjusting.
The cleaning device according to claim 12 or 13, characterised in that the means comprise infiltrated air slits or a flap or a grate.
The cleaning device according to any one of the preceding claims, characterised in that at least one measuring device is provided to measure the input stream and/or output stream and/or the waste material.
The cleaning device according to claim 15, characterised in that the measuring device measures the pressure and/or the volume flow and/or the colour difference of the material.
17. The cleaning device according to any one of the preceding claims,
characterised in that a regulating and control system is provided to make adjustments.
|Indian Patent Application Number||2397/CHENP/2007|
|PG Journal Number||27/2013|
|Date of Filing||04-Jun-2007|
|Name of Patentee||MASCHINENFABRIK RIETER AG|
|Applicant Address||KLOSTERSTRASSE 20, CH-8406 WINTERTHUR, SWITZERLAND|
|PCT International Classification Number||D02G 3/04|
|PCT International Application Number||PCT/CH05/00630|
|PCT International Filing date||2005-10-27|