Patent GB-1116007-A (GB)
Title: Spinning head for melt-spinning synthetic filaments
IPC: D01D4/08
Filed: 1966-03-03
Abstract: 1,116,007. Spinning heads for melt spinning. INVENTA A.G. FUK FORSCHUNG UND PATENTVERWERTUNG. 3 March, 1966 [3 March, 1965], No. 9417/66. Heading B5B. As illustrated in Fig. 3 the spinning head comprises a spinning head for the melt spinning of filaments of organic thermoplastic material, a housing 10 provided with an inlet 4 and a skirt 20, a spinneret plate holder 11, a filter 3 surmounted by a pressure plate 12, a filter support plate 2 and a spinneret plate 1. The spinneret plate holder 11 is provided with a flange 18 supporting the spinneret plate and the latter, the filter 3 and the housing 10 are urged together by tightening a ring nut 14 which threadably engages a screw thread on the lower portion of the inner surface of the skirt 20 of the housing 10. The nut 14 bears on the annular gasket or sealing ring 6 of plastically deformable material surrounding and contacting the bevelled outer surface of the spinneret plate holder 11 the cylindrical upper portion of which is a close sliding fit in the housing 10. The cross-section of the sealing ring or gasket 6 is rectangular when the gasket is not under compression, but when the nut 14 is tightened down on to it the gasket is urged into sealing engagement with the bevelled surface of the spinneret plate holder 11 and the inner surface of the skirt 20 of the housing 10, as illustrated in Fig. 4. The gasket has then become plastically deformed so that its cross-section is triangular. As the gasket softens and weakens in use, the spinneret holder 11, being a " floating " member which is a sliding fit in the housing 10, the melt entering the spinning head under pressure forces the spinneret holder down on the gasket whereby the seal between the holder and the housing skirt remains effective. A second annular gasket 5 is located on the flange 18 of the spinneret plate holder 11 supporting the spinneret plate 1, and as this gasket softens and/or becomes thinner, the pressure of the melt forces the spinneret plate down on to the flange 18, whereby the gasket 5 remains effective. Melt entering the spinning head through the inlet 4 flows through one or more capillaries 13 in the pressure plate 12 and owing to the resistance to the flow of melt through the capillaries, the melt pressure in the chamber 15 between the plate 12 and the filter 3 is less than that between the upper surface of the plate and the housing. The pressure plate 12 is a close sliding fit in the spinneret plate holder 11 which is therefore forced down on to the spinneret plate by the difference in melt pressure between the upper and lower surfaces of the pressure plate. The spinning head may be provided with a non-threaded metal ring bearing on the gasket 6, the ring being forced on to the gasket by an annular row of bolts passing through holes in the ring and screwed into the skirt of the spinning head housing. Owing to the portion of the periphery of the spinneret holder 11 engaged by the gasket 6 having a bevelled or frusto-conical shape, the initial tightening of the ring 14 on to the gasket 6 and the subsequent forcing of the spinneret holder downwards by the pressure of the melt introduced into the spinning head causes the gasket 6 to be firmly wedged between the housing skirt 20 and the bevelled portion of the spinneret holder periphery, the radial pressure on the gasket 6 being much higher than the melt pressure, an efficient seal thus being assured.