US3500499A

US3500499A - Spinning device for synthetic fibers

Info

Publication number: US3500499A
Application number: US642870A
Authority: US
Inventors: Gunter Goossens
Original assignee: Inventa AG fuer Forschung und Patentverwertung
Current assignee: Inventa AG fuer Forschung und Patentverwertung
Priority date: 1965-03-03
Filing date: 1967-06-01
Publication date: 1970-03-17
Anticipated expiration: 1987-03-17
Also published as: NO120378B; BE677301A; FI44146B; CH432711A; GB1116007A; AT282806B; LU50560A1; DE1660375A1; NL6602709A; ES323682A1

Description

March 17, 1970 e. GOOSSENS 3,500,499

SPINNING DEVICE FOR SYNTHETIC FIBERS Filed June 1, 1967 2 Sheets-Sheet 1 PRIOR ART F I62 A PRIOR ART I J 1 6 I X\ I I INVENTOR. GUNTER GOOSSENS I IMIII i cam w March 17, 1970 a. GOOSSENS 3,

SPINNING DEVICE FOR SYNTHETIC FIBERS Filed Jfine 1. 1967 2 Sheets-Sheet 2 PRIOR ART I 1 l \fl 2/ 5/ ,INVEN'TOR. GUNTER eoosssns United States Patent Int. Cl. D01d 5/18 US. Cl. 18-8 3 Claims ABSTRACT OF THE DISCLOSURE A device for spinning of synthetic fibers containing filters, wherein the principle of selfsealing is applied and the external positions to be sealed and gasketed are limited to only two. Leaking of the device is eliminated and the working life of the gaskets increased.

This application is a continuation-in-part of my copending application Ser. No. 533,386, filed Mar. 3, 1966.

In the spinning of synthetic fibers, the spinning dope is extruded from the spinneret or spinning head at comparatively high temperatures, e.g., 300 C., and at relatively high pressures, e.g., 200 kg./cm. through filters and nozzles or spinning jets. Sealing problems arise thereby. It hardly is feasible to elastically prestress the sealing surfaces sufficiently to retain the required contact pressure throughout long spinning times, despite plastic deformation of these surfaces under the prevailing pressures and temperatures. The solution of the problem of proper sealing meets with further difliculties because the two principalparts of the device, i.e., the nozzle plate and the filter, must be readily exchangeable. Moreover, because of the need for a large number of spinning machines, simple and expensive devices are preferred. The clogging of filters and of spinning jets, furthermore, pressure leaks are the principal causes for changing of the spinning devices after a certain operating time.

The problem of maintaining the surface pressure on the gaskets even when they, under the influence of pressure and temperature, undergo plastic deformation, can be solved by the utilization of what is known as the principle of selfsealing (or selfpacking). Thereby, the inherent pressure of the spinning dope is utilized. The spinning machines are constructed in such a manner that the sealing surfaces are not driven apart under the pressure of the dope, but are compressed, and that the parts to be sealed follow the plastic deformation of the gaskets by changing their positions.

Whereas the principle of selfsealing has been considered in the construction of spinning machines, it has been used merely in part. Construction of a spining machine solely in keeping with this principle has not been realized to date despite the many advantages deriving therefrom. Hence, the maximal possible working life of nozzles or jets and filters could not be utilized because of the unduly short working life of the gaskets.

It now has surprisingly been found that a spinning ma chine can be built using the principle of selfsealing exclusively and limiting the number of external positions to be sealed and gasketed to two. The machine for spinning of synthetic fibers otherwise works in the conventional manner, i.e., the dope flows from the spinning head through the filters, which rest on support plates, to the nozzle plate which contains the spinning jets.

The spinning process executed in the device according to the invention has been known for a long time and consists in forcing the viscous material through a nozzle plate containing a plurality of fine orifices. Fibers form thereby which immediately solidify. The material to be spun is a polymer melt or solution, e.g., polyamide or polyester.

While the device according to the invention had in the first place been designed for spinning from a melt, it had been found that it is equally suited for spinning from solutions. The device comprises, aside from the nozzle plate, filter elements and an encapsulation of all-these components which is constructed in a novel manner and assures complete sealing without leakage even under the most severe operating conditions. Simultaneously, the device is easily operated and maintained, and exchange of parts, when required, is readily accomplished. This contrasts from older modes of construction wherein frequent leakage requires frequent exchange of parts.

Upon melt spinning the temperature and pressure conditions previously named are encountered.

The invention now will be more fully explained with reference to the accompanying drawings in which like parts are shown by identical reference numerals. However, it should be understood that these drawings are to serve merely as illustration, and not of limitation, and that it is intended to cover all modifications of the invention which do not depart from the spirit and the scope of the invention as hereinafter claimed.

In the drawings, all of which are schematics in plan view,

FIGS. 1-3 are different embodiments of conventional spinning machines;

FIG. 4 is an embodiment of the present invention.

Upon melt spinning, the actual spinning devices are sunk in cavities disposed in the spinning head housing of the machine. The housing furthermore contains the conduits for the melt which usually are introduced into the spinning devices by means of special measuring pumps. The spinning head housings are heated to prevent solidification of the melt. Because the spinning devices are sunk in cavities adapted to their contours, they are protected from cooling. Gaskets are disposed at the discharge end of the melt conduits into the devices, at the edges of the melt filters and at the edges of the nozzle plates, which must meet extremely high requirements due to the severe operating conditions. Leakages, for instance, cause great expenses because they interrupt production and require additional operations, such as exchange of leaking devices, their dismantling, cleaning, reassembly, installation of new filters and gaskets, and ensuing preheating of the next charge. The device according to the invention is of such a constructionthat leakages cannot occur and that exchange of parts for other reasons is facilitated because removal and reinstallation are readily accomplished.

The spinning apparatus shown in FIG. 1, known heretofore, consists of a nozzle plate 1, a filter support plate 2 disposed above nozzle plate 1 and sealed by the gasket ring 9. There further is a filter 3, resting on the filter support plate 2 and provided with a frame 8 which acts as a gasket. The housing 11, together with eye bolt 16, holds the entire apparatus together with the force with which the eyebolt 16 had been tightened. With the aid of a ring 17 and a number of bolts 18, the device consisting of the parts named above is held in a cavity in the spinning head housing 10. The latter has an intake bore 4 for the dope, and this bore continues through the body 15. The passage is sealed by gasket 7. The latter is pressed tight by bolts 18.

During the operation of the device, filter 3 and nozzle plate 1 exert a considerable flow resistance against the melt entering at 4, which must be overcome by high pressure of the melt. The melt under high pressure within the cavities between nozzle plate 1 and support plate 2, also between filter 3 and body 15, counteracts the contact pressure of eye bolt 16, whereby housing 11 is slightly stretched in longitudinal direction. This effects a diminished contact pressure on the

gaskets

9 and 8. These gaskets must be of a plastically deformable material in order to closely join uneven spots in the sealing surfaces. They partly change position, due to the diminished contact pressure and the high pressure with which the melt acts on them from the interior of the device in radial direction, and thereby are squeezed out of the seams which they are to seal, so that leakage ensues.

By the resistance which the entire device exerts on the flowing melt, pressing the nozzle plate downwardly, ring 17 and bolts 18 also attain an additional load so that the contact pressure on the gaskets 7 is decreased and the latter also is prone to leak.

FIG. 2 shows a spinning device which is inserted from the top in a corresponding cavity in spinning head housing 10. The melt is introduced from the side through conduit 4 and enters the device after passing gasket 7. The contact pressure on gasket 7 is provided by means of bolt 19. Here again the pressure of the melt counteracts the contact pressure of gasket 7 adversely.

Nozzle plate 1, gasket 9, filter support plate 2, and filter 3 with its frame 8, are similar to the corresponding parts in FIG. 1 and are held together between the body 15 and ring 17 by means of bolts 18. Under the pressure of the melt, the individual parts again are pressed apart so that a counteraction occurs against the contact pressure of

gaskets

9 and 8, generated by the bolts 18. Thereby the bolts 17 are stretched in longitudinal direction and leakage easily takes place.

FIG. 3 is a certain improvement on a device inserted from the top. The action of gasket 7, obtaining its contact pressure from a bolt 19, is the same as that in FIG. 2 and, hence, has the same disadvantages. However, a gasket is disposed below nozzle plate 1. The pressure exerted by filter 3 and nozzle plate 1 against the flowing melt urges these parts downwardly whereby the contact pressure on gasket 5 is not counteracted, but is increased with rising pressure of the melt so that leakage at this part is precluded. By the pressure of the melt, which is generated in the flat space between filter 3 and body 15, the latter is raised like the piston of a hydraulic press and urged against gasket 6 which is propped upwardly by bolt 16. Due to the conical shape of the upper edge of body 15 gasket '6 now is widened and radially urged against the inner wall of housing 11, so that here alsb a sealing effect is attainedwith which the contact pressure increases with rising pressure of the melt instead of being decreased.

Gasket 8 in FIG. 3 consists of a frame of filter 3 and is not a seal toward the outside, as is the case in FIGS. 1 and 2. However, sealing is required because otherwise parts of the melt bypass the filter, thus flowing into the nozzle orifices in unfiltered state and clogging the same. Experiments with devices according to FIG. 3 have shown that this is a serious peril, and it has been found that body 15 rises while deforming gasket 6 so that the edge 8 of filter 3, framed with sheet metal, no longer fits the edge of filter support 2. It has further been found that some of the nozzle orifices clog after a few hours. When edge 8 is urged onto filter support plate 2 by means of a bolt, this clogging is avoided for a considerable length of time. However, the application of such a bolt complicates the entire installation procedure and renders the device more expensive.

A spinning device similar to that in FIG. 3 has been disclosed in US. Patent 2,871,511. It differs from that of FIG. 3 merely by using a sand filter which is not different in principle. In the drawing of said patent, the spinning head housing corresponding to 10, gasket 7 and bolt 19, of FIG. 3 are not shown. The gasket 7 of FIG. 3 whose contact pressure is not aided by the pressure of the melt is not included in the patent, However, the gasket which seals the passage from thehousing to the' device and which, according to the present invention, also is under pressure by the melt, is a salient part of the latter.

The device according to the invention has a number of advantages over the prior art. It has merely two gaskets to the outside including the gasket at the passage of the melt conduit from the spinning head housing to the spinning device proper. Both these gaskets are under pressure by the melt in the interior of the device. The limit of two gaskets is an advantage in itself. Whereas the cit'd patent names two gaskets, those seals between spinning head housing and spinning device are not shown in the disclosure and the drawing.

The present invention provides one further gasket which, however, is internal to prevent the melt from bypassing the filter. This gasket also is under pressure from the melt. A further advantage of the invention resides in the easy installation and assembly of the component parts which merely are laid into each other without tightening any bolts. This saves labor in the preparation of the spinning device for its application.

The advantages of the device according to the invention will be shown with reference to FIG. 4 which illustrates its particular, novel construction. A bell-shaped hollow body 11 is held, by means of a support ring 14 in a correspondingly shaped cavity in a spinning head housing 10 in such a manner that 11, having the shape of a cylindrical hollow body provided with a bottom on one side, is connected, by means of a gasket 5, to the edge of the intake bore 4 in housing 10 and is disposed so as to be upwardly movable in vertical direction to such an extent as gasket 5 permits when the latter is compressed by an upward movement of hollow body 11. The latter contains in its interior, nearest to the bottom, a press plate 12 which has at least one small bore 13. Bore 13 connects with little clearance to bore 4. The lower edge of press plate 12 abuts on the edge of filter 3 which has a sheet metal frame and lies on filter support plate 2. The latter, in turn, rests on nozzle plate 1 which has a conical edge, supported by a gasket 6 which preferably is angular and, even more preferred, of rectangular cross section. The superposed parts consisting of press plate 12, filter 3, filter support plate 2 and nozzle plate 1 within the interior of the bell-shaped hollow body 1, are disposed in a downwardly movable manner in vertical direction to such an' extent as gasket 6 permits when compressed by such a downward movement. Gasket 6 rests on the upper edge of support ring 14 whereby the interior of said edge is directed inwardly. Ring 14 is detachably connected to housing 10 and surrounds the lower edge of the bellshaped hollow body 11.

The melt flowing through conduit 4 enters the device after passing gasket 5. The device according to the invention consists of the

compartment parts

1, 2, 3, 5, 6, 11, 12 and 14 and constitutes an exchangeable unit which is sealed from the outside by the nozzle plate 1, the bellshaped hollow body 11, and support ring 14.

After passing gasket 5, the melt is forced to flow through the comparatively small bore 13 of press plate 12 which exerts a hydraulic resistance thereon so that the pressure before bore 13 increases, and the melt enters the space between press plate 12 and the bottom of body 11 under this pressure. The melt thus lifts the hollow body 11 and urges the same against gasket 5 so that the principle of selfsealing is attained. Moreover, the melt in said space urges the press plate 12 downwardly so that the spaces between the plate and the sheet metal framed filter 3 (constituting the previously named internal seal) between it and filter support plate 2 and between it and the nozzle plate 1 also are compressed and sealed. This has the effect that the filter cannot be bypassed and that no unfiltered melt can reach the nozzle orifices. Gaskets made of plastically deformable material are not required since such negligible quantities of melt which possibly might travel through the compressed spaces cannot contain contaminants of any appreciable size and are to be regarded as filtered. Nozzle plate 1 transfers the hydraulic forces which are generated by the flow through bore 13,

filter 3 and the fine orifices of the nozzles and which are directed downwardly, to gasket 6. The latter, due to the conical shape of the edge of the nozzle plate, is forcibly widened and pressed radially in outward direction onto the inner wall of hollow body 11, since downward yielding of gasket 6 is prevented by support ring 14. Thus, selfsealing again is attained. Support ring 14 transfers the vertically directed hydraulic forces to the spinning head housing with which it is detachably connected, e..g., by means of screw threads.

Whereas in the preceding description the spinning dope had been named as a melt, it should be understood that the device according to the invention can equally be used for spinning solutions.

The device has a number of features which also are used in those according to prior art, such as filter support plates and filters, nozzle plates and gaskets per se. However, the salient and novel features of the invention are the bell-shaped hollow body, the press plate, and the coaction and interaction of the parts, as previously described.

I claim as my invention:

1. A device for the spinning of synthetic fibers from a dope, said device consisting essentially of a spinning head housing having an intake bore for said dope; a bell-shaped cylindrical hollow body, fitted within a closure on one side and having an outer contour conforming to the interior of said housing, disposed within the spinning head housing; a gasket connecting said hollow body to said intake bore, said hollow body being movable toward and within the limits of said gasket when the latter is under compression from inflowing dope; a press plate disposed within the limits of said gasket when the latter is under one bore smaller than said intake bore, thus providing pressure for the inflowing dope, and abutting with little clearance on said intake bore; a metal edged filter disposed on said press plate opposite the side nearest the intake bore, said metal edge supporting the press plate; a filter support plate at the opposite side of said filter; a nozzle plate having a conical edge; a second gasket supporting said nozzle plate; means for the supply of dope; said press plate, filter support plate, filter, and nozzle plate being laid one on another, and being movable toward and within the limit of said second gasket when under compression from the inflowing dope; and a detachable support ring aflixed to said housing, and surrounding the edge of said hollow body, said detachable support ring urging said second gasket against said nozzle plate.

2. The device as defined in claim 1, wherein said second gasket is angular.

3. The device as defined in claim 2, wherein said second gasket is of rectangular cross section.

References Cited UNITED STATES PATENTS 2,879,543 3/1959 McDermott. 3,229,330 1/1966 Perrier et a1. 3,259,938 12/ 1966 Martin. 3,353,211 1l/l967 Heynis.

WILLIAM J. STEPHENSON, Primary Examiner PC4050 w 3,500,499 Dated March 17, 1970 M Patent No.

VE Gunter Goossens t is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 6, at line 2, change the limits of said gasket when the latter is under" -said hollow body, said press plate having at least-- SIGNED AND SEALED JUL 141970 (SEAL) .Attest:

WIELLIAM 80W JR. Edward M. Fletcher, Ir. Commissioner 01 Pat mfl. Attesting Officer