Patent GB-833642-A (GB)
Title: Nozzles for the extrusion of filament-forming or other materials
IPC: D01D5/34
Filed: 1956-02-28
Abstract: An extrusion nozzle which may be used for the spinning of organic textile fibres has at least one sleeve-like extrusion passage along which filament forming material can be passed to an extrusion orifice, the passage being delimited by an internal nozzle tube having an axial duct for the passage of gas or a liquid which may be filament-forming material or by a generally cylindrical member containing two or more such internal nozzle tubes, and by a surrounding nozzle tube which is connected with the internal nozzle tube by <PICT:0833642/IV (a)/1> <PICT:0833642/IV (a)/2> <PICT:0833642/IV (a)/3> <PICT:0833642/IV (a)/4> <PICT:0833642/IV (a)/5> <PICT:0833642/IV (a)/6> <PICT:0833642/IV (a)/7> <PICT:0833642/IV (a)/8> <PICT:0833642/IV (a)/9> <PICT:0833642/IV (a) <PICT:0833642/IV (a)/123> <PICT:0833642/IV (a)/134> <PICT:0833642/IV (a)/145> <PICT:0833642/IV (a)/156> <PICT:0833642/IV (a)/167> <PICT:0833642/IV (a)/178> <PICT:0833642/IV (a)/189> axially-spaced projections.  As shown in Figs. 2a and 2b, in a spinning nozzle consisting of three concentric tubes Di, Dm and Da of an alloy of 75 parts gold and 25 parts silver and having three extrusion orifices all in the same plane at the nozzle face, the innermost tube Di is the longest and the outermost tube Da the shortest, the intermediately positioned tube being of intermediate length.  The tube Dm is integrally joined to the inner nozzle tube Di in two positions along its length by radial projections as shown in one position in Fig. 2a.  Similarly, the tube Da is joined to the tube Dm as shown in Fig. 2b, which also shows the joint between tubes Di and Dm in the second position, the radial projections between tubes Di and Dm being displaced 90 degrees with respect to the corresponding radial projections in the first position along the nozzle axis.  As shown in longitudinal section in Fig. 1, a spinning head having a number of spinning nozzles D arranged in a circle at the extrusion face of the spinning head, each nozzle comprising three concentric tubes and having three extrusion orifices, comprises a supporting body 23 which in turn comprises four parts, namely three rings 24 and a distributer top member 25.  The supporting body 23 includes four bodies of revolution 23b to 23e of trumpet-shaped longitudinal section fitted into one another, the innermost body 23b being solid and the outer bodies 23c to 23e being hollow.  Three channels 23i, 23m and 23 are formed by clearances between the bodies 23b to 23e, which channels serve as conduits for the supply of spinning material to the spinning nozzles D.  The four bodies 23b to 23e are preferably shrunk on one another and their relative positions fixed by spacer pins 26.  The sleeve-shaped channels 23i, 23m and 23a of annular transverse section terminate at the exterior of the supporting body 23 in parallel circumferential ring grooves of semi-circular cross-section.  Three annular channels, also of semi-circular cross-section, and corresponding with the three annular channels on the exterior of the body 23, are provided on the inner surface of the ring member 24 which, when in position, secures a number of nozzles D to the circumference of the supporting body 23.  The upper or inlet end of the innermost tube Di of one of the nozzles D is shown enlarged in Fig. 3, the upper end of the tube Dm being shown in Fig. 4 on the same scale.  As shown in Figs. 5 to 7, in order to mount the nozzles D on the body 23, each nozzle D is coated with a layer 27 of dental phosphate cement and pressed with the aid of a tool 28 into a vertical groove of semi-circular cross-section formed in the exterior of the supporting body 23.  The surplus cement is then cut away and the rings 24 are shrunk on to the body 23.  As shown in Fig. 4, to prevent the nozzle ducts from becoming clogged with cement during the mounting of the nozzles in the spinning head, the inlets of the nozzle ducts may be temporarily sealed with blobs 29 of some sealing material which may subsequently be removed by means of a solvent.  As shown in Figs. 3 and 4, the nozzles D are so arranged in the spinning head that the inlet of each duct in the nozzles is located approximately at the centre of the horizontal annular duct of circular cross-section formed by the opposing grooves in the parts 23, 24 of the spinning head.  The possibility of clogging of the inlets by solid impurities in the spinning material is thereby minimized.  The outlet ends of the nozzles D may extend beyond the under-surface of the supporting body 23a, as shown in Fig. 27. The building up on the bottom of this body of deposits of the spinning material extruded from the outer annular extrusion orifice of the nozzle D is thereby also minimized.  The nozzle D, before mounting in the body 23, is preferably temporarily filled with a substance which is not readily deformed and which can subsequently be dissolved away, e.g. a synthetic resin soluble in organic solvents or a metal soluble in acids.  Distortion and crushing of the nozzle while it is being mounted in the body 23 is thus prevented.  The cement layer 27 may alternatively consist of a metal electrolytically deposited on the nozzle D, as shown in Figs. 8 and 9.  The nozzle duct inlets are first sealed with blobs p  of lacquer 29 and the portions of the metallic nozzle exterior still left exposed then have electro-deposited on them a thick layer of soft porous gold 30.  The nozzle is then mounted on the body 23 in the manner previously described.  The distributer top member of the spinning head shown in Fig. 1 is provided with feed lines 31 for spinning material and annular milled recesses communicating with the annular ducts 23i, 23m and 23a.  The members 25 and 23 are preferably provided with flanged joint faces.  In another embodiment of the invention, shown in Figs. 27 and 28, the spinning head comprises four nozzle supporting members ti, tm, ta and tk and six three-orifice spinning nozzles of identical construction, such as that shown in Figs. 29 and 30.  A cylindrical central recess 1 having a "roof" shaped like a truncated cone and communicating with an annular duct Sr of circular cross-section is provided in the flat base of each of the members ti, tm and ta and is surrounded by an annular tongue which fits accurately into an annular groove 4 provided in the top of each of the members tm, ta and tk. The top of each of these members is provided with a cylindrical conical-topped boss or projection 3 surrounded by the annular groove 4, which boss fits accurately into the cylindrical portion of the recess 1 of the member above.  The members ti, tm, ta and tk can thus be brought into accurate alignment with one another when they are drawn together by means of bolts 8, and the joints between them are rendered liquid-tight by means of gaskets 5 of chemically-resistant deformable material, such as gold or lead, in the grooves 4.  The spinning nozzles may also be of the type shown in Fig. 31 in which the nozzle tubes di, da and dm have thickened walls 51 located at the levels of the gaskets 5 in order to render the tubes more resistant to deformation when the gaskets are subjected to compression.  As shown in Fig. 32, the portions of the nozzle tubes in the zones 52 between the gaskets 5 may be slightly curved to render the tubes resilient and to allow for thermal expansion and contraction.  As shown in Fig. 33, the concentric nozzle tubes di, dm and da of a triple extrusion orifice spinning nozzle may be connected together by a helical rib 71.  The axial lengths of the projections 3 (Fig. 27), on the members tm, ta and tk are less than those of the recesses 1 into which they fit, thus leaving cavities or clearances S which serve as feeding chambers for the ducts in the nozzles d, the inlet ends of which ducts are located in the horizontal annular ducts Sr. Ducts Zi, Zm and Za are provided in the supporting members for the supply of filament-forming material to the chambers S.  The spinning nozzles may be made by electrodepositing a layer of hard gold to a depth of 10m  on a copper or silver wire of 10m  diameter.  A layer of copper or silver is in turn electrodeposited to a depth of 20m  on the layer of hard gold, and at a desired position along the electroplated wire recesses are ground or machined to a depth sufficient to remove locally the outside layer of copper or silver and expose the under layer of hard gold, some of this being preferably also removed.  A further layer of hard metal is then electrodeposited to a depth of 20m  on the layer of copper or silver and also in the recesses directly on to the underlying layer of hard gold, the two hard gold layers thus being integrally united at the recesses, as shown in Fig. 14. The upper part of the partly finished nozzle, including the junction between the two hard layers, is now coated with a lacquer, and a layer of copper or silver is electrodeposited to a depth of 20m  on the remainder of the nozzle not coated with lacquer.  Recesses are formed in this outer layer of copper or silver in the manner previously described and an outermost layer of hard gold is in turn deposited on the copper or silver layer. The nozzle is then cut at the position 19, Fig. 19, in such a manner that the lacquer layer and the underlying hard metal layer are completely cut, while the innermost hard metal layer is not penetrated.  The nozzle is also cut at the position 20 in such a manner that only the outer hard metal layer is cut.  The nozzle is then cut to the required length and the lacquer and copper or silver temporary portions of the nozzle are dissolved away with appropriate solvents.  An alternative method of forming nozzles by electrodeposition of acid insoluble and acid-soluble metals and subsequent removal of the latter by treatment with acids is also described.  The nozzles may be used for the production of hollow filaments, in which case a gas is passed throu