Textiles: spinning – twisting – and twining – Apparatus and processes – Open end spinning
Patent
1986-10-31
1988-03-15
Watkins, Donald
Textiles: spinning, twisting, and twining
Apparatus and processes
Open end spinning
57408, 57411, D01H 7892, D01H 7882
Patent
active
047304510
DESCRIPTION:
BRIEF SUMMARY
This invention relates to apparatus for making a yarn, comprising two juxtaposed, closely spaced apart twisting drums, which are adapted to be driven in the same sense and define between them a generally triangular twisting space, and an inclined fiber-guiding duct, which communicates with fiber-opening means and protrudes into the generally triangular twisting space between the twisting drums and serves to supply singled fibers in an entraining air stream into the generally triangular twisting space.
When fibers supplied through a fiber-guiding duct into a generally triangular twisting space between two twisting drums rotating in the same sense are twisted together in said generally triangular twisting space to form a yarn, or when covering fibers supplied into the generally triangular twisting space are wound in said space around a drawn roving which is pulled through the generally triangular twisting space, the strength and uniformity of the resulting yarn will essentially depend on a uniform and directed supply of the fibers into the generally triangular twisting space. The fibers which have been singled by preceding fiber-opening means should be substantially parallel and uniformly distributed as they are supplied to the generally triangular twisting space so that irregularities will not occur in the resulting yarn as a result of a random orientation and irregular distribution of the fibers. Said requirements cannot be met, particularly if the single fibers delivered in an entraining air stream tend to form lumps as they travel through the fiberguiding duct.
For this reason it is an object of the invention so to improve by the use of simple means a yarn-making apparatus of the kind described first hereinbefore that a directed and uniform supply of fibers into the generally triangular twisting space will be ensured without a risk of a formation of lumps.
The object set forth is accomplished in accordance with the invention by entraining the singled fibers in an air stream having a mean velocity of flow corresponding to a Reynolds number of 5,000 to 50,000 in a shortest boundary wall of the fiber-guiding duct whose shortest boundary wall facing the generally triangular twisting space has a length which is at least as large as the average length of the longest fibers to be processed in the apparatus, the ratio of the length to the width of the flow area of the duct being between 10:1 and 2:1.
Because the minimum length of the shortest boundary wall of the fiber-guiding duct matches the average length of the longest fibers which can be processed by the apparatus, it is ensured that a flow path of adequate length is provided in which the singled fibers entrained by the entraining air stream are oriented in the direction of flow. As a result, the singled fibers which are entrained by the entraining air stream will substantially extend along the flow lines as said fibers enter the generally triangular twisting space. Because the fiber-guiding duct protrudes into the generally triangular twisting space between the two twisting drums, the width of the cross-section of said duct is limited by the open width of the generally triangular twisting space adjacent to the mouth of the fiber-guiding duct. In order to permit a flow of entraining air through the fiber-guiding duct at an adequate rate, on the one hand, and to ensure a desirable extent of the mouth of the fiber-guiding duct in the direction of yarn withdrawal, as is significant for a uniform tying of the supplied fibers into the fibrous structure of the yarn being formed, the flow area of the fiber-guiding duct must have a substantial longitudinal extent. Important requirements for a uniform supply of fibers will be fulfilled if the ratio of the length to the width of the generally rectangular flow area is between 10:1 and 2:1. But in addition to the stated conditions it will be essential to ensure that the entraining air stream will have such a velocity of flow that individual fibers will not fall out of the entraining air stream and that a formation of l
REFERENCES:
patent: 4570434 (1986-02-01), Stahlecker
patent: 4601167 (1986-07-01), Fuchs
patent: 4606187 (1986-08-01), Stahlecker
patent: 4607485 (1986-08-01), Stahlecker
Kelman Kurt
Textilmaschinenfabrik Dr. Ernest Fehrer Aktiengesellschaft
Watkins Donald
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