Method and apparatus for carding of staple fibers

Abstract

The present invention relates to a method and apparatus of carding staple fibres like cotton. More particularly, the present invention is directed to an apparatus for carding of staple fibres with minimum number of moving parts and to reduce the need for close tolerances, especially where moving parts are involved, in order improve the manufacturability of the apparatus. Density of input tufts to the carding machine is reduced. Diameter of carding cylinder (7) is reduced, with corresponding increase in its rotational speed, to maintain the peripheral speed. An air guiding element (6) and at least air deflection elements (8) used for capturing long fibres on a perforated roller. This enables elimination of close-set moving parts and simplifications of design. Advantageously, the present invention minimizes the damage to the fibres so that they retain their natural and desirable properties.

Description

FIELD OF INVENTION[0001]The present invention relates to a method and apparatus of carding staple fibres like cotton. More particularly, the present invention is directed to an apparatus for carding of staple fibres with minimum number of moving parts and to reduce the need for close tolerances, especially where moving parts are involved, in order to improve the manufacturability of the apparatus. Advantageously, the present invention minimizes the damage to the fibres so that they retain their natural and desirable properties.DESCRIPTION OF PRIOR ART[0002]Carding is a process that takes tufts of fibres as input, removes the trash and short fibres contained in them and individualizes the fibres to finally deliver a uniform web of these individualized fibres.[0003]In conventional carding machines, the tufts of fibres are fed to the apparatus by a cylindrical rotating member termed as feed-roller and a specially contoured stationary member termed as feed-table that presses against the...

AI Technical Summary

Benefits of technology

The present invention aims to provide a carding machine that reduces stresses on fibers, while keeping them in their natural and desirable properties. This is achieved by ensuring a gentle carding action, achieved by using a low density of input tufts, which reduces the need for heavy calendaring rolls. The tufts are presented directly to the carding cylinder by a feed-roller rotating relative to a feed-table, instead being picked up by an intervening licker-in cylinder. This arrangement eliminates the need for a separate licker-in, as the input materials are presented in a favorable condition.

Problems solved by technology

These features render the fibres vulnerable to breakage, apart from requiring high precision in manufacture and setting of the clearance between the nose and the licker-in cylinder.

Either the machine has to be stopped periodically for this or a complicated and costly arrangement of “revolving flats” is used so that the flats can be cleaned without stopping the machine.

Also, the fibres experience high stresses due to the mechanical action in various parts.

This leads to significant damage to the fibre, which loses several desirable properties it possesses in its natural state.

This poses formidable challenges in manufacturing and therefore impact the cost of the carding machine.

Moreover a well-known challenge in carding is the problem of re-circulating fibres—fibres that circulate multiple times around the cylinder because of inefficient doffing.

These fibres reduce the effective area available on the carding cylinder for fresh fibres that are fed, necessitating a reduced feed rate to compensate for it, thereby reducing the machine productivity.

However, forced draught of air requires substantial power, apart from greater complexity in construction in order to provide leak-free enclosures and ducts.

It is obvious that all these methods come with significantly increased complexity, costs and performance overheads.

The need to selectively remove short fibres before carding has been an issue of significant importance, because short fibres choke the carding flats and reduce the efficacy of their action.

While such inventions are directed at improving the performance of the carding machine by adding additional components, it is also recognized that the machine is very bulky, heavy and entails expensive manufacturing operations to achieve acceptable levels of precision.

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