Plastic article or earthenware shaping or treating: apparatus – Distinct means to feed – support or manipulate preform stock... – Extrusion shaping means
Patent
1995-08-09
1997-08-19
Woo, Jay H.
Plastic article or earthenware shaping or treating: apparatus
Distinct means to feed, support or manipulate preform stock...
Extrusion shaping means
425114, 425145, 264 407, 264 459, B29C 4790
Patent
active
056585985
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND
The invention relates to a secondary coating line for producing a secondary-coated optical fibre or bundle of fibres, the line comprising a feeding apparatus with a feed roll for feeding an optical fibre or bundle of fibres; an extruder for extruding an oversize secondary jacket around the fibre or bundle of fibres; a cooling apparatus for cooling the extruded secondary jacket, the distance between the extruder and the point where the cooling apparatus starts to cool being adjustable; and a winding apparatus for winding the finished secondary-coated fibre or bundle of fibres on a take-up roll.
A conventional secondary coating line with the basic structure described above is known e.g. from Finnish Patent 75,939, or corresponding British Patent Application 2,141,557. Conventionally, secondary coating lines like this have been controlled so that a product produced during the starting and speeding up of the line has not met the quality requirements. The reason for this is that when the speed of the line changes, the characteristics of the produced secondary coating also change; not until the normal running speed is achieved does the secondary coating reach the desired values. A rather large amount of valuable optical fibre has thus been wasted.
Alternatively, optical fibres have not been thread into the tube provided by the secondary jacket until the production speed has been achieved. Plastic waste has been produced, and the production speed must have been adjusted to be so slow that it has been possible to thread the optical fibres into the secondary jacket at that rate.
When optical fibres are thread into the secondary jacket at a rate that is slower than the normal running speed, the poor quality of the product is at least primarily due to the fact that the distance between the cooling apparatus and the extruders has not been suitable considering the rate. In practice, the plastic melt outlet from the press head forms after the press head a conical part in which the secondary jacket tube is drawn to its final measurements. If the water cooling conducted in the cooling apparatus is started at the conical part, the result is a brittle tube, i.e. the tensile strength of the tube in a tension test is small. If on the other hand the distance between the press head and the water cooling is too long, the hot plastic may run, causing faults in shape and variation in diameter. As the line speed increases, the tension cone following the press head becomes larger; by suitably adjusting the line speed, it has thus been possible to make the measurements of the secondary jacket comply with the quality requirements.
In secondary coating, the type of plastic from which a secondary jacket is produced must also be taken into account. Since different plastic types have different characteristics, they behave differently in an extruder, and so the plastic melt also behaves differently and the line speed must be suitable in order that it might be possible to achieve the desired measurements.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a new kind of secondary coating line by which the quality of the secondary-coated optical fibre or bundle of fibres can be maintained high irrespective of the plastic type used, the line speed, or possible controlled changes in the line speed during the production process. This is achieved with the secondary coating line of the present invention, which is characterized by comprising means for determining the point where the cooling apparatus starts to cool, means for determining the speed of the finished secondary-coated fibre or bundle of fibres, and means for adjusting the point where the cooling apparatus starts to cool in accordance with the speed of the finished secondary-coated fibre or bundle of fibres.
Thus the basic idea of the present invention is that if the point where the cooling is started is adjusted in accordance with the line speed, the final product always meets the quality requirements, irrespective of the line speed. Advantageously
REFERENCES:
patent: 4229392 (1980-10-01), Shimano et al.
patent: 4536365 (1985-08-01), Zwick
patent: 4585603 (1986-04-01), Furuta et al.
patent: 4592881 (1986-06-01), Kyriakis
patent: 4744930 (1988-05-01), Twist et al.
patent: 5084227 (1992-01-01), Vancoppenolle et al.
patent: 5151147 (1992-09-01), Foster et al.
patent: 5213689 (1993-05-01), Kafchinski et al.
patent: 5494623 (1996-02-01), Sato et al.
Nokia-Maillefer Oy
Schwartz Iurie A.
Woo Jay H.
LandOfFree
Secondary coating line does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Secondary coating line, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Secondary coating line will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1102898