Coating processes – With stretching or tensioning – Running lengths
Reexamination Certificate
1999-05-27
2001-07-10
Bareford, Katherine A. (Department: 1762)
Coating processes
With stretching or tensioning
Running lengths
C427S428010, C427S429000, C118S264000, C118S266000, C492S017000, C057S295000
Reexamination Certificate
active
06258406
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This is a national phase application of PCT/EP 98,/06029, filed Sep. 22, 1998.
BACKGROUND OF THE INVENTION
The present invention relates to a godet for applying a liquid to an advancing yarn wherein the yarn is advanced over the outer surface of the godet as the godet rotates about its axis and wherein the liquid is applied in measured quantities to the surface of the godet so as to be applied to the yarn.
DE 29 08 404 discloses a method and an apparatus for applying a liquid to an advancing yarn. The apparatus is formed by a driven godet, which comprises radially peripheral surface areas that can be wetted. A metering device applies the liquid for lubricating the yarn in measured quantities to the surface of the godet. The yam advances over the wetted surfaces in contact therewith and thus receives its coating of the lubricant.
This known method has the disadvantage that the liquid made available on the surface for lubricating the yam decreases as the circumferential speed of the godet increases. Thus, a slowly advancing yarn is offered a relatively large quantity of liquid and a fast advancing yarn a relatively small quantity of liquid. Consequently, fast advancing yarns at a speed greater than 3,000 m/min can be lubricated by this method only inadequately.
DE 43 33 716 discloses a method and an apparatus, wherein the godet surface comprises a groove. In this groove, a liquid for lubricating a yarn is sprayed from the outside. For the lubrication, the advancing yarn is guided over the groove of the godet. Likewise, this method shows the tendency that a small amount of liquid is offered to a relatively fast advancing yarn for its lubrication.
It is therefore the object of the invention to improve a method and an apparatus of the initially described kind, so that they ensure a uniform lubrication of a yarn regardless of its speed.
SUMMARY OF THE INVENTION
The above and other objects and advantages of the present invention are achieved by the provision of a godet which defines a cylindrical outer surface, and which includes a plurality of substantially radially oriented capillaries formed in the godet and communicating with the outer surface so as to define openings on the outer surface which are distributed circumferentially thereabout. Also, a liquid supply device is connected to the capillaries for supplying a liquid to the capillaries and thus to the openings on the outer surface.
In use, the liquid is metered onto the outer surface of the godet through the capillaries and openings, and the openings are distributed over the surface of the godet. Thus, metering of the liquid is determined by the diameters of the capillaries, the number of the capillaries, as well as the rotational speed of the godet. By merely increasing the rotational speed of the godet and, thus, the surface speed, the quantity of the liquid emerging from the capillaries increases. With that, it is possible to use the method as well as the apparatus even at higher yarn speeds of more than 3,000 m/min without subjecting the lubrication effect to a change.
To lubricate one or more yarns, it is preferred to drive the godet by a motor. However, both the method and the apparatus of the present invention also offer the possibility of constructing the godet without a drive. In this instance, the yarn or yarns drive the godet. A speed control would here be possible, for example, by means of an adjustable brake. The metering is directly determined by the yarn speed. Thus, due to the centrifugal force at high yarn speeds and, with that, at high circumferential speeds of the godet, a larger quantity of liquid is present on the surface of the godet that is contacted by the yarn.
A further advantage of the invention lies in that the liquid emerging from the surface distributes very evenly over the surface. This permits metering the liquid that is applied to the yarn.
Likewise, the path of the advancing yarn never dries, since the liquid is constantly supplied to the yarn even from the bottom.
The method will be especially advantageous and efficient, when the liquid is supplied to the capillaries inside the godet. The liquid is guided without losses to the surface of the godet. The transfer into the capillaries occurs alone due to the centrifugal forces.
The capillaries extend in the surface areas that serve to lubricate the yarn. However, it will be especially advantageous, when the pore-sized openings of the capillaries are evenly distributed over the entire surface on the circumference of the godet. With that, it is possible to realize a very uniform lubrication in that the yarn loops about the godet several times. In particular, in the case of low yarn speeds, it will be possible to lubricate therewith several, parallel guided yarns at the same time. To this end, the yarns advance over the godet parallel with a multiple looping.
The variant of the method, wherein the capillaries are formed in a sleeve that is slipped over the godet casing distinguishes itself in particular in that a varied metering is to be realized in a simple manner irrespective of the rotational speed of the godet. In this connection, a sleeve slipped over the godet casing may be replaced with a second sleeve having differently configured capillaries.
To obtain a great evenness of the capillaries, it will be especially advantageous to make the sleeve of a sintered material.
To lubricate several yarns evenly with one godet, the variant of the method is especially advantageous, wherein the yarn advances with a partial looping on the godet circumference. To this end, in one embodiment of the apparatus according to the invention the pore-sized openings of the capillaries are evenly arranged within a plurality of parallel juxtaposed, radially peripheral surface areas of the godet casing or sleeve. Each of the surface areas forms a path for wetting a yarn.
In a particularly advantageous embodiment of the apparatus according to the invention, the liquid supply to the capillaries in the sleeve proceeds through a plurality of grooves arranged in the godet surface that is covered by the sleeve. In this connection, the grooves may be formed in the godet surface radially, axially or spirally. The grooves connect to the liquid supplying device, so that the liquid required for lubricating the yarn is continuously present within the groove.
The diameters of the capillaries, the number of capillaries, as well as the rotational speed of the godet determine the amount of liquid available on the surface for lubricating the yarn. The diameter of the capillaries that is selected as a function of the yarn denier is preferably in a range from 10 &mgr;m to 1,000 &mgr;m. In this connection, a number of capillaries are selected that covers from minimally 2% to maximally 75% of the surface.
REFERENCES:
patent: 4773136 (1988-09-01), Seydel et al.
patent: 879 582 (1980-02-01), None
patent: 2 317 053 (1974-07-01), None
patent: 29 08 404 (1985-10-01), None
patent: 41 13 339 (1992-10-01), None
patent: 43 33 716 (1995-02-01), None
patent: 0 173 432 (1986-03-01), None
patent: 2 064 604 (1981-06-01), None
Patent Abstracts of Japan, vol. 5, No. 156 (C-074), Oct. 6, 1981 & JP 56 085410 A (Toyobo Co Ltd), Jul. 11, 1981.
Enders Ulrich
Reichwein Markus
Alston & Bird LLP
Bareford Katherine A.
Barmag AG
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