Patent GB-1083240-A (GB)
Title: Spinneret
IPC: D01D5/32
Filed: 1966-08-15
Abstract: 1,083,240. Spinneret. E. I. DU PONT DE NEMOURS & CO. Aug. 15, 1966 [Aug. 25, 1965], No. 36370/66. Heading B5B. A spinneret assembly for producing conjugate filaments of two or more components comprises a spinneret plate 12 having a downstream face and an upstream face, a meter plate 14 having a downstream face and an upstream face, a plurality of supply sources 34, 36, and a means for supplying polymers to each of said supply sources, characterized in that (a) said spinneret plate 12 has one or more nozzles 20 located therein, each of said nozzles having an orifice 22 at the downstream face of said spinneret plate and a large entrance hole 24 at the upstream face of said spinneret plate; (b) the downstream face of said meter plate 14 is juxtaposed to the upstream face of said spinneret plate; (c) a plurality of expansion chambers 26, 27 are located in the downstream face of said meter plate, two or more of said expansion chambers being positioned above each of said entrance holes 24 and in communicating relationship therewith; (d) the supply sources 34, 36 are located upstream of said expansion chambers; and (e) a metering hole 28 connects each expansion chamber to a supply source. The supply sources may, as shown, be chambers 38, 44 located in the downstream face of a sand-holder 16, said sandholder being positioned upstream of the metering plate 14, and the downstream face of said sandholder being juxtaposed to the upstream face of said meter plate. Alternatively, the supply sources may be chambers in the upstream face of the metering plate. Preferably, as shown, two of said expansion chambers 26, 27 are positioned above each of said entrance holes 24. As shown, supply chamber 30 is an annular cavity in the upstream face of meter plate 14, and supply chamber 32 is a similar but smaller annular cavity concentric with supply chamber 30. Alternatively the supply chambers can be a number of circular holes. In modifications, the supply chambers 30 and 32 may be eliminated, or the grooves 38 and 44. Another variation is to eliminate all the supply chambers and grooves 30, 32, 38 and 44 and have holes 40 feed directly to metering holes 28 and holes 42 and 43 feed directly to metering holes 29. In operation, filtration means such as sand or screens are inserted in the central cavity 34, and sand is inserted in the sand-holder 36. In operation, polymer F is supplied to central cavity 34, and leaves through a plurality of holes 42 and 43 which feed the annular groove 44, which is in a matched relationship with supply chamber 32. Polymer F is then metered to each individual spinning nozzle by metering hole 29. Polymer is forced through the small diameter metering hole 29 as a high velocity jet, but when this jet reaches expansion chamber 27, of relatively large diameter, the velocity of the polymer is reduced and the polymer now moves at a low rate of speed from the expansion chamber into entrance hole 24. In a similar manner, polymer S is supplied to annular cavity 36, which is filled with sand or screens so as to filter the polymer S in a similar manner as polymer F is filtered by sand or screens in cavity 34. The polymer S is then supplied through holes 40 into annular cavity 38 and supply chamber 30, then through metering hole 28 into another expansion chamber 26. Thus polymer S is fed into entrance hole 24 as a slow moving stream. Thus the two polymers F and S are brought together as slow-moving streams in a side-byside relationship. Since they are slow moving, this greatly reduces the tendency for mixing, especially in the high-viscosity polymers used to form synthetic filaments. The two side-byside polymer streams are then brought to an increasing velocity by the shape of the bottom of the spinneret nozzle and issue from orifice 22 in the form of a high-velocity jet. At this point there is no tendency for the polymers to intermix as they have already assumed the desired side-by-side relationship. The filament crosssection obtained with the spinneret assembly of the invention is shown in Fig. 2. While spinneret assembly 10 is for two-component sideby-side filaments, more than two components or two polymers may be used. Further, while the pack illustrated provides for a circular pattern of spinning nozzles 20 on the spinneret plate 12, and the various holes and cavities in meter plate 14 and spinneret plate 12 and sand-holder 16 are located accordingly, it is possible to use the same basic concept for a spinneret having the spinning nozzles aligned in rows.