Opening machine and an opening method

Abstract

An opening machine for separating the fibres from intermingled impurities in cotton tufts comprises a storage bin into which cotton tufts to be processed are introduced, and an opening cylinder associated with cleaning blades for separating the impurities from the fibres and with suction openings for removing the impurities and the fibres separately. The opening machine comprises a pre-opening roller for performing a preliminary opening of the tufts. The cotton material is withdrawn from the bin by feed rollers, is processed by the pre-opening roller, and is introduced into a chamber in the form of pre-opened tufts. A final feed roller withdraws the tufts from the chamber and supplies them to the opening cylinder. The final feed roller works at a withdrawal rate greater than that of the feed rollers to prevent accumulation of the tufts in the chamber.

Description

[0001] The present invention relates to an opening machine for separating the fibres from intermingled vegetable impurities in cotton tufts, of the type defined in the preamble to claim 1. The invention also relates to a method of opening cotton tufts and the like.

[0002] Conventional opening machines comprise an upper storage bin or supply chamber into which the cotton tufts to be processed are introduced. At the bottom of the storage bin there is an opening cylinder (with prongs, needles or clothing) which cooperates with cleaning blades to split up the fluffy masses of cotton at least partially into their individual constituent fibres, eliminating the intermingled vegetable impurities (parts of leaves, of capsules, of seeds, earth, etc.) therefrom. In the vicinity of the opening cylinder there are usually suction openings for removing the impurities separated from the fibres and a duct through which the impurity-free fibres are removed.

[0003] An example of this known technology is provided by U.S. Pat. No. 4,858,277.

[0004] In conventional opening machines, the material in tufts usually reaches the opening cylinder in the form of a compact mat. When the material is processed in the compacted condition, the opening cylinder cannot achieve good separation of the fibres from the vegetable impurities, unless a clothing having quite "aggressive" characteristics towards the material to be treated is selected for the opening cylinder. However, a clothing of this type brings about the breakage of a considerable quantity of fibres.

[0005] An object of the present invention is to provide an opening machine which can eliminate the disadvantages of the prior art discussed above. In particular, it is an object of the invention to provide an opening machine which can bring about improved cleaning efficiency, that is, which can achieve better separation of the vegetable impurities from the fibres, without damaging the fibres.

[0006] Another object of the invention is to provide an opening machine which can operate with a shorter working cycle.

[0007] These and other objects and advantages which will be understood further from the following are achieved, according to the invention, by an opening machine having the characteristics defined in claim 1.

[0008] According to a further aspect of the invention, a method comprising the steps defined in claim 15 is proposed.

[0009] A preferred but non-limiting embodiment of an opening machine and of an opening method according to the present invention will now be described with reference to the appended drawing, which is a schematic, vertically-sectioned view of an opening machine according to the invention.

[0010] With reference to the drawing, an opening machine according to the present invention is generally indicated 10. The general structure of the opening machine shown in FIG. 1 may be considered generally known; only the elements which are of specific importance and interest for the purposes of the implementation of the invention will therefore be described in detail in the following description. For the construction of the parts and of the elements which are not described in detail, reference may therefore be made to any known opening machine.

[0011] The opening machine 10 comprises a substantially vertical storage bin 11 in the upper portion of which there is an intake device 12 connected to a duct 13 for the supply of cotton tufts from the exterior.

[0012] In the lower portion of the opening machine there is a conventional opening cylinder, indicated 14, associated with conventional cleaning blades 15, carding segments 16 and openings 17 for the suction and removal of the impurities separated from the fibrous portion of the cotton tufts. The fibres, on the other hand, are removed by suction through a duct 18.

[0013] An important characteristic of the solution according to the invention is that, in the lower portion of the bin 11 in which the tufts to be processed are stored, there is a set of three rollers which can perform a preliminary opening operation on the tufts and can supply the tufts to the opening cylinder 14 in a controlled manner and in an at least partially-opened and non-compacted condition.

[0014] Two feed rollers 19 and 20 are arranged substantially side by side in the lower portion of the storage bin 11 and are rotated in the directions indicated by the arrows in order to withdraw, in a metered manner, the material which is usually in a compacted condition in the base of the storage bin 11, and to supply this material, in a less dense condition, to a pre-opening roller 21.

[0015] The feed roller 19 has projecting peripheral elements 19a adapted to force the tufts of material to fall into the passage between the rollers 19 and 20.

[0016] The feed roller 20 has an outer clothing 20a which serves to restrain the cotton tufts whilst they are located in the narrow passage between the rollers 20 and 21 and are subjected to a rubbing action by means of elements 21a projecting from the periphery of the pre-opening roller 21. Since the pre-opening roller 21 is rotated at a tangential velocity considerably greater than that of the clothed roller 20 and of the feed roller 19, it brings about, by means of the outer elements 21a, a preliminary or at least partial opening of the tufts which are dragged along by the clothing 20a of the clothed feed roller 20. By way of indication, the feed roller 20 rotates at a tangential velocity of between 1.5 and 4 m/min., whereas the preopening roller 21 rotates at a tangential velocity of between about 400 and 600 m/min.

[0017] Preferably, a passage having a width of between 0.5 and 2 mm, and most preferably of about 1 mm, is defined between the clothing 20a of the roller 20 and the ends of the elements 21a of the pre-opening roller 21.

[0018] The tufts, in a partially-opened condition, are thus thrown by the peripheral elements 21a of the rotating pre-opening roller 21 into an intermediate supply chamber 22 disposed immediately upstream of the opening cylinder 14 and of a feed roller 24 associated therewith.

[0019] It is important to note that the feed roller 24, which is disposed in the lower opening of the intermediate chamber 22, is rotated at a tangential velocity greater than that of the feed rollers 19 and 20 so as to prevent accumulation of material in the intermediate chamber 22. In other words, the material coming from the pre-opening roller 21 reaches the final feed roller 24 in the form of non-compacted tufts. The speed of rotation of the final feed roller 24 is preferably regulated in a manner such as to supply the material to the cylinder 14 with a theoretical delivery rate about 10.div.50 times greater, preferably about 30 times greater, than the delivery rate of the feed rollers 19 and 20, or the quantity withdrawn from the base of the bin 11 thereby per unit of time.

[0020] Moreover, since the peripheral elements 21a of the preopening roller 21 can exert a pumping action on the air, towards the chamber 22, the chamber preferably has a grating or perforated plate 23 which allows the air to escape and thus prevents the formation of undesired excessive air pressure inside the chamber.

[0021] The individual partially-opened cotton tufts are then passed from the chamber 22 to the opening cylinder 14 by means of the final feed roller 24. Since the cotton tufts reach the opening cylinder 14 in an already partially-opened condition, the cylinder 14 can advantageously have finer or less aggressive clothings in order to process the cotton tufts more effectively and to separate their fibrous cotton fraction from the impurities without damaging or breaking the fibres.

[0022] Naturally, the principle of the invention remaining the same, the details of construction and forms of embodiment may be varied widely with respect to those described and illustrated, without thereby departing from the scope of the invention as defined in the appended claims.

Claims

What is claimed is:

1. An opening machine for separating the fibres from intermingled impurities in cotton tufts, of the type comprising: a storage bin into which cotton tufts to be processed are introduced, an opening cylinder associated with means for separating the impurities from the fibres and with means for removing the impurities and the fibres, separately, from the opening machine, the machine further comprising roller pre-opening means which are interposed between the storage bin and the opening cylinder and which can cooperate with one another to perform a preliminary opening operation on the tufts and to supply the tufts to the opening cylinder, in controlled manner, in an at least partially-opened and non-compacted condition.

2. The opening machine of claim 1, wherein the roller pre-opening means comprise a pre-opening roller which can be rotated at controlled speed and which has projecting peripheral elements suitable for exerting an at least partial opening action on the tufts.

3. The opening machine of claim 2, wherein the peripheral elements are inclined slightly in the direction of rotation of the pre-opening roller.

4. The opening machine of claim 2, wherein the roller pre-opening means further comprise at least one second roller which is operatively associated with the pre-opening roller and which can be rotated at a controlled tangential velocity, in the same direction of rotation as the pre-opening roller, in order to exert the at least partial opening action on the tufts.

5. The opening machine of claim 4, wherein the second roller has a clothing suitable for temporarily restraining the tufts thereon to permit at least partial opening of the tufts by means of the peripheral elements of the pre-opening roller.

6. The opening machine of claim 4, wherein the second roller is located upstream of the pre-opening roller.

7. The opening machine of claim 4, wherein the pre-opening means further comprise a third feed roller, located upstream of the pre-opening roller and beside the second roller, in order to cooperate with the second roller in the supply of the tufts from the storage bin to the pre-opening roller.

8. The opening machine of claim 4, wherein the pre-opening roller is rotated at a tangential velocity greater than that of the second roller.

9. The opening machine of claim 1, wherein it comprises a supply chamber located in an intermediate position between the roller pre-opening means and a final feed roller associated with the opening cylinder, the supply chamber being suitable for allowing the material to pass through in a non-compacted and partially-opened condition.

10. The opening machine of claim 9, wherein: the final feed roller which supplies the material withdrawn from the intermediate supply chamber to the opening cylinder, and the rollers of the roller pre-opening means which withdraw the material from the storage bin, have dimensions such, and/or are driven in a manner such, as to prevent accumulation of material inside the intermediate chamber.

11. The opening machine of claim 10, wherein the final feed roller is arranged to supply the material from the intermediate chamber to the opening cylinder with a delivery rate no less than the amount of material withdrawn from the storage bin by the roller pre-opening means per unit of time.

12. The opening machine of claim 11, wherein the final feed roller is arranged to supply the material from the intermediate chamber to the opening cylinder with a theoretical delivery rate about 20-50 times greater than the delivery rate of the roller pre-opening means, or the quantity of material withdrawn from the storage bin thereby per unit of time.

13. The opening machine of claim 9, wherein the intermediate chamber comprises vent means for eliminating excessive air pressure.

14. The opening machine of claim 15, wherein the vent means comprise a perforated plate or grating defining one of the walls of the intermediate chamber.

15. The method of opening cotton tufts and the like by means of an opening machine according to claim 1, the method including the steps of: a) introducing cotton tufts to be processed into a storage bin, b) withdrawing the cotton material from a lower region of the bin by means of roller feed means, c) pre-opening the cotton material withdrawn by the roller feed means, by means of a pre-opening roller rotated at controlled speed and having projecting peripheral elements suitable for exerting an at least partial opening action on the tufts, d) introducing the tufts into an intermediate chamber in an at least partially-opened condition, e) withdrawing the tufts from the intermediate chamber by means of a final feed roller operatively associated with an opening cylinder, f) opening the tufts by means of the opening cylinder, separating the impurities from the fibres, and removing the impurities and the fibres, separately, from the opening machine.

16. The method of claim 15, wherein the step e) of the withdrawal of the tufts from the intermediate chamber is achieved by adjustment of the speed of the roller feed means and of the speed of the final feed roller in a manner such as to prevent accumulation of the cotton material in the intermediate chamber.

17. The method of claim 16, wherein the final feed roller is rotated in a manner such as to supply the material from the intermediate chamber to the opening cylinder with a theoretical delivery rate about 10-50 times greater than the delivery rate of the roller pre-opening means, or the quantity of material withdrawn from the storage bin thereby per unit of time.