Patent GB-677016-A (GB)
Title: A process and device for reducing the diameter of non-metallic continuous fibres
IPC: D01D10/04
Filed: 1949-09-14
Abstract: <PICT:0677016/IV (a)/1> <PICT:0677016/IV (a)/2> Non-metallic continuous fibres are exposed to the action of a liquid bath which attacks the fibres physically or chemically, and simultaneously a flow of gas bubbles is caused to act on the fibres, the bubbles being caused to separate from the fibres as far as possible at regular intervals.  Thus the action of the bath liquid in reducing the diameter of the fibres may be controlled. The gas bubbles which adhere to the surface of the fibres, may be detached by sound waves or by supersonic waves.  If, as is preferred, the liquid of the bath is subjected to electrolysis, to produce gas bubbles, during the passage of the fibres through it, an alternating current having a high number of cycles may be imposed upon the direct current used for the electrolysis, or as an alternative a pulsating direct current may be employed.  The gas bubbles may, however, be introduced into the bath from an outside source if desired.  Fine gas bubbles give the best results; such bubbles may be produced by using a cathode having fine pores and of larger overall size than the anode.  As shown, in a container 1 are arranged two electrodes 2, 3, the cathode 3 being larger than the anode 2, which is made of material resistant to the liquid of the bath (e.g. of platinized sheet, or coated with platinum sponge).  The threads pass from a reel 7 through the bath by means of guide rollers 5 and 6 and are supported by members 4 and collected on reel 8.  The reels and/or rollers may be suitably driven.  To avoid collection of gas beneath the anode, this may be designed as a metal net, grid or perforated sheet.  If it is desired to superimpose an alternating current on the direct current, a second anode 11, also formed as a grid is provided, and is preferably made of a metal having a higher polarizing voltage than cathode 3.  The process is of particular application to fining glass fibres, using a bath of dilute hydrofluoric acid or dilute alkali (if the glass is alkali-soluble). It may also be applied to cellulose threads in a bath of cuprammonium solution, or to cellulose acetate in a mixture of acetone and methyl or ethyl alcohol.  In this latter case, if the flow of gas is to be produced electrolytically, the solvent should also contain a small amount of water.ALSO:Non-metallic continuous fibres are exposed to the action of a liquid bath which attacks the fibres physically or chemically, and simultaneously a flow of gas bubbles is caused to act on the fibres, the bubbles being caused to separate <PICT:0677016/IV (c)/1> <PICT:0677016/IV (c)/2> from the fibres as far as possible at regular intervals.  Thus the action of the bath liquid in reducing the diameter of the fibres may be controlled.  The gas bubbles, which adhere to the surface of the fibres, may be detached at regular intervals of time by sound waves or by supersonic waves.  If, as is preferred, the liquid of the bath is subjected to electrolysis, to produce gas bubbles, during the passage of the fibres through it, an alternating current having a high number of cycles may be imposed upon the direct current used for the electrolysis, or as an alternative a pulsating direct current may be employed.  The gas bubbles may, however, be introduced into the bath from an outside source if desired.  Fine gas bubbles give the best results; such bubbles may be produced by using a cathode having fine pores and of larger overall size than the anode.  As shown, in a container 1 are arranged two electrodes 2, 3, the cathode 3 being larger than the anode 2, which is made of material resistant to the liquid of the bath (e.g. of platinized sheet, or coated with platinum sponge).  The threads pass from a reel 7 through the bath by means of guide rollers 5 and 6 and are supported by members 4 and collected on reel 8.  The reels and/or rollers may be suitably driven.  To avoid collection of gas beneath the anode, this may be designed as a metal net, grid or perforated sheet.  If it is desired to superimpose an alternating current on the direct current, a second anode 11, also formed as a grid is provided, and is preferably made of a metal having a higher polarizing voltage than cathode 3.  The process is of particular application to fining glass fibres, using a bath of dilute hydrofluoric acid or dilute alkali (if the glass is alkali-soluble). It may also be applied to cellulose threads in a bath of cuprammonium solution, or to cellulose acetate in a mixture of acetone and methyl or ethyl alcohol.  In this latter case, if the flow of gas is to be produced electrolytically, the solvent should also contain a small amount of water.