METHOD AND PLANT FOR SUBSEQUENT TREATMENT OF ROPES MADE OF ARTIFICIAL FIBRES

Abstract: By the making of rope (6) of synthetic fibres, the rope is treated with a water based impregnating agent from which the water is evaporated in a drying oven (4), before the rope (6) is transferred to a setting oven (14). Normally, hot gas is used for heating in the drying oven (4) but by the invention tangible advantages are achieved by using HF heating by means of opposite HF electrode plates in connection with a continuous rope passage, where the rope (6) appears as an elongate body during the passage of the drying oven (4). By the invention it is furthermore indicated that the rope (6), by the continuous advancing, may be subjected to an advantageous stretching in a simple way by being actively pulled out from the setting oven (14) from a braking capstan drive (10, 12) at the inlet of the setting oven (14).

Description: Method and Plant for Subsequent Treatment of Ropes Made of Artificial Fibres The present invention concerns a method and a plant for finishing treatment of rope made of synthetic fibres. It is common that ropes of this kind are impregnated with water base polyurethane and acrylic, as the water is evaporated subsequently in a drying oven, and the rope is passed on to a setting oven. By this process, it is prior art to use a special drying oven in which a great length of rope may be hanged in bights between upper and lower guide rollers, after which a top and side cover are lowered for enclosing the rope. The subsequent setting oven in which the impregnation is set at about 140°C may be arranged in a corresponding way, and it may be heated by a gas burner, the flue gas of which is utilised as heat source in the drying oven. Usually, after the setting oven there is provided a cooling zone with blast of cold air so that the rope immediately thereafter may be brought to coiling without any risk of adhesive action between the rope coils. By the invention it has been realised that a technique, which is improved in several respects, may be indicated, in that high frequency heating is used for heating in the drying oven by means of HF electrodes disposed at opposite sides of the oven compartment, and where the rope appears as an elongate item during the passage of the drying oven. It has been ascertained that the F£F heating will be tangibly more economical than heating by flue gas, namely as a consequence of the HF energy only being deposited in the water to be evaporated. However, furthermore there will also be achieved the effect that the water by its close contact with the rope fibres induces heating of the rope, which may then cause a minimised power supply to the setting oven. The use of HF heating for drying coiled yarn items, and thread coiled on bobbins, are known from GB A 2 143 934, F A 2 704 633, FR A 2 739 999 and US 4 304 048, respectively. This method is possible to use on coiled yarn/thread since the mass thereby heated is relatively small, and thereby also the amount of liquid to be evaporated in the drying oven. The coiled yarn/thread will thus not be overheated to such a degree that sticking occurs between the layers on the bobbins. Application of the same principle as indicated in the above prior art in drying rope of the indicated kind coiled on reels will not be possible, as the amount of heat deposited in the rope in connection with the HF drying for drying it will cause individual windings to stick to each other due to melting. Therefore, it is of importance that we are speaking of drying rope where the rope appears as an elongate object. It is a further and significant circumstance that in connection with HF heating, it is practically possible to make a change to a continuous processing technique, whereby the oven compartments may be kept closed and besides may be built with minimal size for treating rope lengths of even very great length. Hereby the whole procedure becomes considerably simpler, and the rope heated indirectly in the HF drying oven may be transferred to the setting oven without any appreciable drop in temperature. Just by such a continuous handling it is also made possible in a simple way to subject the rope to other desirable treatment, namely a stretching by which all the rope fibres may be straightened to a mainly axial direction with the result that the rope, apart from an increased length, may show a breaking strength improvement of about 10%. Such a continual stretching may be developed on the whole rope length through the setting oven and the cooling zone in that the rope, which generally is advanced via a capstan drive after the cooling zone, passes a corresponding though braking capstan system at the inlet to the setting oven so that the rope is subjected to stretching during the whole intermediate passage. The braking capstan may be held braked by means of an electric generator contributing to the driving of the pulling capstan, so that the work may be performed by hybrid action with a limited power consumption for the rope stretching. The invention is explained in the following with reference to the drawing, in which: Fig. 1 is a schematic draft of a plant for finishing treatment of rope according to the invention, Fig. 2 is a top view of the plant shown in Fig. 1, and Fig. 3 is a side sectional view of a HF oven in which the rope is dried. Fig. 4 is a top view of the HF-oven shown in Fig. 3. By the plant shown in Figs. 1 and 2, initiation is made from a rope unwinder 2 for a rope 6 which is already soaked with a water-based, heat activating impregnating agent, but the case could as well be a continual supply of rope which is supplied from a rope laying machine via a passage station (not shown) for such impregnation of the rope 6. The rope 6 is discharged for its further passage with a certain brake action in the unit 2. From there, the rope 6 is led further on through a drying oven 4, where, in the shown embodiment of the plant, it is passed through some loops 7 via guide rollers (Fig. 3 and Fig. 4) where it passes a number of opposite HF electrode plates 9 for driving out the water phase of the impregnating agent by evaporation. The guide rollers 5 and the loops 7 are adapted so that the rope 6 does not change its structure when passing these and the HF electrode plates 9. The rope 6 may then, in dried and simultaneously heated state, be passed out through a narrow, though not particularly sealed hole 8, to a capstan system 10 which acts with braking the further advancing of the rope. However, the rope is pulled actively by a subsequently positioned capstan drive 12 as the rope is hereby stretched and advanced in stretched condition through a setting oven 14 firstly, and then through a cooling zone 16 while it, after the pulling capstan drive 12, is passed further on to a winding station 18. The rope is not necessarily to be passed straight through the units 14 and 16, as it may very well be led in stretched bights, around pulleys both at the top and at the bottom, as well as in the HF oven 4 so that necessary stay times in respective units may, however, be attained. As mentioned, the capstan system 10 will act as brake on the rope before the capstan drive 12, but the system 10, which via a braking generator supplies power to the drive 12, will, however, appear as the unit pulling off the rope from the unwinder 2, which itself is made with a mechanical brake, i.e. really, this pulling off also occurs by the force from the drive 12.

Claims: CLAIMS 1. A method for finishing treatment of ropes (6) made of synthetic fibres by which the rope (6) is treated with a water-based impregnating agent and then is brought to a drying oven (4) for evaporating the water and subsequently to a setting oven (14) for setting the impregnating agent, characterised in that the heating of or in the drying oven (4) is effected by applying high frequency energy between opposite HF electrode plates in the oven chamber, and where the rope (6) appears as an elongate object during passage of the drying oven (4). 2. A method according to claim 1, characterised in that the rope (6) is heated during continuous passage of the drying oven (4). 3. A method according to claim 2, characterised in that the rope (6) is ad- vanced by continuous passage during the entire treatment in the drying oven (4), the setting oven (14) and a succeeding cooling chamber (16). 4. A method according to claim 1 or 3, characterised in that the rope (6) is imparted a permanent elongation in connection with the finishing treatment. 5. A method according to claims 3 and 4, characterised in that the elongation is imparted by means of controlled capstan drives (10,12) along a passage between the outlet (8) from the drying oven (4) and the outlet from the setting oven (14) or the cooling chamber (16). 6. A plant for performing the method according to claim 1, comprising a drying oven (4) for evaporating water from newly impregnated ropes (6) supplied to this oven, characterised in that the drying oven (4) is designed for high frequency heating of the water phase in the intermediate rope (6) conveyed through the drying oven (4) as an elongate item. 7. A plant according to claim 6, characterised in that it has been provided with means for continuous advancing of the rope (6) through the drying oven space. 8. A plant according to claim 6 and furthermore including a setting oven (14) for the impregnating material dried in the drying oven (4) and a cooling chamber (16) coupled subsequently for the rope (6), characterised in that this has been made with means (2,10,12,18) for continuous passing through of the rope (6) through these units of the plant which are adapted themselves for passing the rope in tight condition. 9. A plant according to claim 8, characterised in that it has been made with means (10,12) for active elongation of the rope (6) at its passage between the outlet (8) of the drying oven (4) and the outlet side of the setting oven (14) or the outlet of the cooling chamber (16), respectively. 10. A plant according to claim 9, characterised in that the means (10,12) for the active elongation of the rope (6) are constituted by a forward capstan drive (10) for exerting a braking action on the rope (6) and a rear capstan drive (12) for exerting a pull in the rope (6) for advancing the latter with higher speed than at the forward capstan drive (10), as the braking capstan (10) preferably is kept braked by means of an electric generator contributing to the driving of the pulling capstan (12).

Inventors: BIE CLAUS, BIE, CLAUS
Applicants: BIE CLAUS, N P UTZON AS, A/S N.P. UTZON, BIE, CLAUS
Application year: 2001
Main classification: F26B23
IPC codes: D02J1, F26B3, F26B13