US2217743A - Apparatus - Google Patents

Description

Oct. 15 2 1940. I w -r 2,217,743

APPARATUS Filed March 2a, 1939 2 sues-Sheet 1 I MINVENTOR p w ATTORNEY 15 19404 c. H. GREENEWALT APPARATUS 2 Sheets-Shem 2 Filed March 28, 1939 INVENTOR Z) M I904 ATTORNEY Patented Oct. 15, 1940 UNITED STATES PATENT oFFIc-E ware 3 Application March 28, masons! No. 204,535 x j '5 2c1'aims.'(c1.1s--s),

This invention relates" to the production of yarns, filaments, ribbons, -and the like by the melt spinning of organic filament-forming compositions. For convenience; but with no intention of so limiting this invention, it will be. discussed in terms of the melt spinning of fiberforming synthetic linear polyamides (superpolyamides) such as may be prepared by the condensation reactions described in U. '5. Patents Nos. 2,071,250, 2,071,251, 2,071,253 and 2,130,948. For convenience, these fiber-forming synthetic linear polyamides-are hereinafter 'referred to as polyamides.

The melt spinning of such compositions is a new art and presents many problemssince it is necessary not only to operate continuously, efficiently, and economically but also to produce products 01' very uniform properties, particularly in the case of textile yarns where uniform denier, uniform dye' aflinity and uniform physical properties are very important.

A besettingproblem in the operation of a plant for the melt spinningot a textile yarn arises from the necessity of heating the melting and 5 spinning apparatus to ahigh temperature before the actual spinning operation can be started and the high temperature at which the apparatus must be maintained throughout the spinning operation. The problem is presented by 30 the time required to put the spinning apparatus into service, to take it out of service, to efiect repairs and/or change of production. It is necessary to carefully maintain the apparatus at these high temperatures with little variation.

This is conveniently done by providing a suit-,

able melting unit and by jacketing the apparatus and passing a fluid heating medium through tubular heating coils in the melting unit and jacket. High pressure steam or Dowtherm 40 (a mixture of diphenyl-diphenyl oxide) may be used as the fluid heating medium. Electric coils may be substituted for the heating coils.

It is often necessary to change the denier and/or filament count of the production, or to repair or adjust a spinning cell because of a defect in some part or operation. When this is necessary, the spinning apparatus must go out of service for a sufficient time for it to come to room temperature and permit mechanics to work 50 on it. Because of the compactness of the design of a commercial spinning plant, the overhauling of the spinning cell in its position interferes with the operation of adjoining apparatus and .is likely to result in the production of inferior 55 yarn in adjacent positions. Finally after the overhaul is completed, it becomes necessary heat the melting-and'spinningfapparatus for a long periodfof timebefore it againreaches an operative temperaturenand;canagain be put.

back into. production. This 'problem of losttime a and interference withnormaljoperation has been found very objectionable;

It is, therefore, an object ofthis invention to provide an improved process. andapparatus for the continuous production of filaments, yarns, 1o

ribbons and the like by the'melt spinning of organic filament-forming compositions.

It is a more specific object of-this invention to provide a combined melting and melt spinning apparatus in which changes in the melting or spinning units, or repairs to these units, can be made withoutv interrupting thespinning at any spinning position for an objectionable period of time.

Other objects of this invention will hereinafter 20 become apparent.

In accordance with the present invention, the above-mentioned objectionable delays and interruptions can be avoided by combining a melting unit and spinning unit in a single assembly which may be interchangeably removed from and connected to a heating shell fixed in a spinning position, as well as to an auxiliary heating shell which is adapted to heat the melting and spinning assembly to operating temperature.

The practice of the invention will become more apparent by reference to the following description and the accompanying illustrations, in which:

Figure 1 is a cross-sectional view of an apparatus illustrative of this invention.

Figure 2 is a side elevational view, with parts shown in section, of the apparatus shown in Figure 1 with the melting and spinning assembly removed from the heating shell.

The spinning apparatus shown in Figure 1 comprises two parts, that represented generally by I, which is a heating shell, and that represented generally by 2, which is a removable melting and spinning assembly.

The heating shell I comprises a rigid shell 4, tubular heating coils 6, and insulating material 8. The coils 3 are supplied with a heating medium such as super-heated steam or Dowtherm by means of inlet pipe l0 and outlet pipe I2.

'The heating shell I is fixed in the spinning position base M. The base I4 and the shell I are provided with an opening I6 for the pump drive shaft it! which can be uncoupled from the metering pump of the spinning assembly and be withdrawn from the base and shell. The rigid shell- 4 is provided with a flange 20 containing holes to receive bolts 22 of the melting and spinning assembly for rigid mounting of parts I and 2 with each other. An opening is shown at 24 for the withdrawal of the spun yarns.

The melting and spinning assembly 2 comprises a hopper 30 for the solid flakes of file-- merit-forming composition, a melting unit 32, a,

container 34 for molten composition, a metering pump 36, and a spinning unit 38. Flakes of filament-forming composition may be passed into hopper 30 through opening 40. While in operation the opening 40 is closed by cover 42. The top of hopper 30 is provided with eye bolts 44 by means of which the melting and spinning assembly may be lifted. The hopper 30' is connected to the frame 48 by means of bolts 46. The heating or melting unit comprising coil 32,

, encased in insulation 50, is positioned between the connecting flanges of the hopper 30, and frame 4t. The insulation 50 prevents the hopper 30 from reaching 'an elevated temperature and prematurely melting the solid filament-forming composition. The melting unit 32 may be heated nected to pump 3tv by conduit 58. The spinning unit 38, including spinneret 60, and the pump 36 are all held firmly in place by means of annular plate 62 which is fastened to flange 64 of frame 48 by means of bolts 66. A gas inlet is shown at III and outlets at 12 and 14 to permit the maintenance of an inert atmosphere in the hopper and above the melting unit, and to remove any air or volatile impurities introduced with the solid filament-forming composition.

In the operation of this invention, the removable melting and spinning assembly 2 is mounted in a heating shell similar in construction to that shown at I but mounted in an assembly room. Solid flakes of the polyamide are introduced into the hopper I I through the opening 40 after which the cover 42 is replaced. The flakes form a solid column resting on the melting unit. The gas inlet is connected with a source of oxygen-free CO: or N: and the apparatus flushed out with a relatively .large rate of flow of gas. The flow of gas at Ill is then reduced and the outlets l2 and 14 adjusted to permit a slow escape of gas from each. The melting unit is connected with a source of heating fluid, preferably from the same source as that used in heating the auxiliary heating shell.

The flakes of material directly in contact with the surface of melting unit 32 melt and the molten material drains to the container 34. As the flakes melt, more flakes come into contact with the melting surface and in turn melt, thereby insuring a constant supply of moltenmaterial. When the assembly has reached the proper'temperature for the spinning of the particular polyamide, the gas inlets and outlets I0, 12 and 14 are closed and the inlet 52 and outlet 54 to the melting unit disconnected. The-entire assembly is then lifted by means of the eye bolts 44 and transported to the already hot shell I, in the spinning room, lowered into it and fixed in position by means of the bolts 22. The flow of gas through the apparatus is then reestablished by the proper connections and adjustments. The

melting unit is again connected to the same source of heating fluid thatenters the shell through inlet ID. The pump shaft "3 is then coupled with the pump mechanism to drive the pump 38.

Spinning is begun when the pump is in operation. The molten polyamide drawn from the container 34 by the pump 35 is metered to the spinning unit 38 from which it is extruded in the form of filaments. The extruded filaments are collected as a yarn bundle in anorderly manner. when it is necessary to repair or adJust the assembly, it is only necessary to disengage the pump drive shaft, disconnect the gas and heating fluid connections, remove the nuts from the bolts 22, whereupon the whole assembly can be removed and replaced by another preheated unit. Delay is thereby reduced to a minimum. If desired, the solid flake need not be added until the unit is in the spinning position since melting is soon effected with the preheated unit.

While this invention has been described with particular reference to the melt spinning of-polyamide filaments, yarns, ribbons and the like, it is not so limited. The apparatus has particular utility for the spinning of molten organic fllament-formlng compositions which are crystalline in the'solid state as evidenced by X-ray investigation. In general, fiber-forming synthetic linear polymers (super-polymers) to which class the superpolyamides belong exhibit this property. Other types of synthetic linear polymers are polyesters, polyethers, polyacetals, mixed polyester-polyamides, etc., such as may, for example, be prepared by a condensation reaction as dacribed in U. S, Patent .No. 2,071,250. Fiberforming polymers prepared by the high pressure polymerization of ethylene, which are more fully described in British Patent No. 471,590 are also crystalline in the solid state.

The invention is also applicable to the spinning of other molten organic filament-forming compositions such as the vinyl polymers, polystyrene and polyacrylic acid derivatives.

The filament-forming material used in the process of this invention may contain modifying agents, for example, lustre-modifying agents plasticizers, pigments and dyes, anti-oxidants, resins, etc. 7

By a practice of this invention it is possible to melt spin filaments, yarns, ribbons and the like from organic filament-forming compositions economically and with a minimum of delay. It is possible to take full advantage of the space and facilities of the spinning area'and to replace or repair defective units or to change the type of production without interfering with adjacent apparatus.

Since it is obvious that many changes and modifications can be made in the above-described details without departing from the nature and spirit of the invention, it is to be understood that,

'unit provided with a flanged housing frame, a

sembly adapted to ill; snugly in said heating shell, and means, positioned on the exterior of said apparatus, for readily connecting and disconnecting said heating shell and said melting and 3 spinning assembly.

'2. A melt spinning apparatus comprising a melting unit and a spinning unit, means connecting said two units securely to each other as a melting and spinning assembly, said spinning

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