US2570171A

US2570171A - Deaeration apparatus

Info

Publication number: US2570171A
Application number: US642991A
Authority: US
Inventors: Kohorn Henry Von; Kohorn Ralph S Von
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-01-23
Filing date: 1946-01-23
Publication date: 1951-10-02
Anticipated expiration: 1968-10-02

Description

Filed Jan. 23. 1946 1951 H. VON KOHORN ET AL 2,570,171

DEAERATION APPARATUS 2 Sheets-Sheet l """J. l A

ATTORN E Y5 1 5 H. VON KOHORN ET AL 2,570,171

DEAERATION APPARATUS Filed Jan. 23, 1946 2 Sheets-Sheet 2.

INVENTORJ 2 M ATTORNEYS Patented Oct. 2, 1951 DEAERATION APPARATUS Henry Von Kohorn and Ralph S. Von Kohorn, New York, N. Y.

Application January-23, 1946, Serial No. 642,991

2 Claims. 1

Our invention pertains. to a methodand apparatus for the continuous manufacture .of rayon, staple ,fiber, transparent'cellulose sheeting, and other cellulose derivatives, by .the viscose method. Our invention eliminates the batch method commonly employed in the manufacture of viscose, and results in a saving of time,aspace, labor, and investment.

.According to our. invention, we place purified cellulose, such as woodqpulp of rayon grade, or bleached cotton linters, on. an endless conveyor belt, or other conveying means. While onsuch conveying means, the cellulosicraw material is first subjected to thenormal steepingprocess or mercerizing, as practised by persons skilled in thelart. 'We then subject thealkali cellulose thus formed to pressure,.suchas between squeeze rollers, .in order to extract excess caustic soda solution, alkali cellulose of known nature resulting from said extracting action. We then subject the alkali celluloseto a shredding or disintegrating action, either by passing it through a continuous shredder, or by chopping it while traveling on an endless belt or conveyor.

After such shredding, disintegrating or chopping :action, we heat the alkali cellulose while continuously traveling on conveyor means, thereafter cooling the alkali cellulose toea' point where the alkali cellulose, thus aged, is readyfor sulfidizing with carbon bisulfide. This method :of ageingfknownras short-ageing, has been described in U. S. Patent No. 2,218,836.

-As an alternative, we first mercerize, then heat, then-extract, in the order set forth, leaving the order of the other steps unchanged, except that the cooling may take place before or'after the extracting step. This alternative has the additional advantage of permitting dissolvedhemiand oxycel luloses, contained or created in the heated alkali cellulose, to be extracted bypressure together with the excess caustic soda solution, thus reducing undesirable components of the :alkali cellulose.

When describing thepreferred sequences of operations according to our process, we do not wish to be limited to the precisely defined time cycles. Certain herein described steps particularly the heating .and to some extent the cooling step, may overlap the time cycle of other steps or take place concurrently with them. Thus, for example, heating may start during mercerizing, even though the mercerizing step itself may just be commencing or may not yet be completed. Cooling may commence during extraction .or shredding, and mayoverlap the first stage of the sulfidizing step. We select theuexact order of steps in'accordance with the nature :of-thecellulose material used, and the properties of the vis cose desired, provided always, however, .thatxthe alkali cellulose, if heated, must be cooled sufiiciently and in time toavoid danger -of-ex-plosion during the sulfidizing step, and prior-to dissolv While the alkali cellulose :is ,still' travelingqon the continuous conveying means, we treat the same with carbon bisulfide, and we preferably carry out this step Whilethe-endless-conveying meansareienclosed in a housing in order towprevent carbon bisulfide fumes from escaping. At the same time, we gent-1y agitate or vibrate the endless convey-ing means inorder to, assure completeand thorough actionof the-carbon bisulfide' on the alkali cellulose-forming xanthate, .as now practisedby persons skilled in the art.

We thereafter continuously feed the :xant-hate into .aamixing tank, feeding at the same time caustic sodasolution to. result in viscose of normal consistency and analysis, as practised by :persons skilled in the art.

Gur mixing or dissolving tank is-constructed :in such-a way as to feed xanthate and caustic .soda solution at one end, and to discharge the viscose at the :other end, in continuous fashion.

The viscose obtained in continuous manner :as described above, is then pumped or forcedby compressed air, and, still in continuous: manner, intorand througha series of pipes or other tanks in ordentogive the viscose an opportunity tov ripen tothe desired degree, dependingron the type of product. desired. :Intermittentlmpr :at one stage of this operation, the viscose .is forced through. a filter-medium-in order to. remove, still in :a continuous mannenany undissolved particles contained in theviscose. After" the desired degreeoffiltration .andripening has been obtained, the viscose is fedintoa vessel which is subjected to :a partial vacuum. 'While slowly and .in continuous manner, passing through .this vessel, or large pipes, the viscose is thus deaerated and is nowready for the spinning, castingv or. other. coagulation andprecipitating steps.

.Our method of continuously de=aerating.vis cosepermits, the viscose to be subjected'to a partial vacuum in suchiaumanner as to present the largest possible surface :and the least depth through which'air or gas must'rise through 'the viscose inorderrtoibe' absorbed by the vacuum. According to -our method,..the viscose. isrpermitted to -spread 'outzhorizontallyi in. suitably. designed vessels :orr;pipes,1thus presenting .eai .large, horn zontal, aggregate surface area to the partial vacuum, and at the same time, reducing the vertical depth or layer of viscose at each particular point. We achieve this by feeding the viscose into a tank equipped with a series of inclined splash or baffie boards, along which the viscose is permitted to flow in a thin layer, said splash or baflie boards being of suitable length, width, and inclination. After deaeration, we collect the viscose again in suitable pipes of usual diameter.

In the drawings, Figure 1 illustrates one embodiment of the vessel used for this purpose. Figure 2 shows a series of pipes through which the tapering exit from the intermediate zone 23a and being of decreasing cross-section from the intermediate zone 23a to the outlet manifold 26. The manifold 22 is provided with an inlet pipe 2| whereas the outlet manifold 26 is connected by way of suitable piping to the inlet of a gear pump 21 driven by a motor 28. The output of the pump 21 discharges through a pipe 29. Furthermore each of the conduits 23 is connected by way of vacuum lines to a suitable vacuum pump which is driven by a motor 32.

In operation a liquid to be de-aerated such as viscose is fed to the inlet manifold 22 through the pipe 2| and is there distributed to the conduits 23. In passing through the inlet end zones 2312 the fluid spreads into a relatively shallow stream and as such flows by gravity downwardly through The viscose is fed into the tank shown in Figure 7 1, or into the pipes shown in Figure 2, at the top, either by gravity, or by means of pumps. It is removed frorrithe tank or the pipes at the bottom, by means of gravity or pumps, and from there transported into intermediary vesels, through additional filters, or to the extruding mechanism.

Figure 1 shows a side elevation and Figure 1A shows a plan view of an apparatus for the continuous deaeration of viscose and other solutions, comprising a closed housing I, the crosssection of said housing being a multiple of the cross-section of the feed pipe 2 for the solution. The solution enters the apparatus through feed pipe 2, inlet header 3, and is distributed by inlet pipes 4. The viscose passes over interior deflecting members 5, having a large aggregate surface and an inclined position so as to permit the solution 6 flowing by gravity and in a controlled path from the top to the bottom of said housing I, to spread out over a large area. The direction of flow is indicated by the arows "I. Vacuum pipe connections M are mounted on housing I, permitting the exposure of all of said interior members and of the solution to less-than-atmospheric pressure. Outlet pipes 8, outlet header 9, gear pump l0 (driven by motor I I), and outlet pipe I 2, represent means for discharging, collecting and removingsaid solution from the lower part of the housing. Vacuum lines M, are connected to vacuum pump l3, driven by motor l5. Deflecting members 5 are mounted in such a way that the lower end of each sheet 5 closely approaches the sheet underneath in order to prevent the liquid from dripping over a considerable height so as to prevent the formation of air bubbles.

Referring now to Figures 2 and 2a of the drawings which illustrate another embodiment of the present invention and wherein Figure 2 is a side elevational view thereof and Figure 2a is a top plan viewthereis provided a horizontal inlet manifold 22 and a horizontal outlet manifold 26 which is parallel to and spaced laterally from and below the inlet manifold 22. A plurality of inclined tubular conduits 23 of circular cross-section connect and provide communication between the

manifolds

22 and 26 and include a major intermediate zone 23a of substantially constant cross- .section and coaxially aligned inlet and

outlet end zones

23b and 23c respectively. The end zone 23b provides'communication between the inlet manifold 22 and the intermediate zone 23a and also provides an outwardly tapering entrance to the intermediate Zone 2311 of increasing cross-section from the manifold 22 to the intermediate zone 23a; Similarly the end zone 230 provides communication between the outlet manifold 26 and the intermediate zone 23a providing an inwardly the intermediate zone 23a in the direction of the arrow 25. The fluid then flows through the end zones 230 into the manifold 26 from where it is removed by the pump 21. The fluid in its passage along to conduits 23 is subjected to sub-atmospheric pressure where de-aeration occurs. This de-aeration is accelerated as a result of the small depth of the fluid stream as it flows along the conduits 23. a

When using an intermediary tank, we place the same under pressure, regulating the level of the viscose in said tank, so as to leave an empty space at the top of the tank. The viscose is forced into said tank by means of a pump or other means, which exert sufficiently strong pressure to force the viscose into the above-described pressure-chamber, thereby overcoming the pressure prevailing in it. Thepressure chamber or tank has an outlet at the bottom, and the viscose in the tank is forced through said outlet. Thus, while viscose is continuously fed into the pressure chamber against the pressure prevailing in it, viscose is also continuously and simultaneously forced out of the pressure chamber by these same pressures. In addition to the pressure de scribed above, the viscose can also be transported by pumps from this vessel in continuous manner into the spinnerettes, casting device, or other extruding mechanism which delivers the viscose into a setting bath, as practised by persons skilled in the art of making rayon, staple fiber, transparent cellulose sheeting, or other cellulose derivatives of the viscose type.

Whereas the chemical'operations as such are the same as those now practised in the viscose products industry, our method of continuously performing said known operations without the use of batches at any stage, is new.

We have explained the principle and mode of operation of our invention and have described embodiments thereof. However, we desire it understood that, within the scope of the appended claims, the invention may be practised otherwise than as specifically illustrated and described.

What we claim is:

1. Apparatus for the de-aerationof viscose or the like, comprising a pair of manifolds relatively disposed in vertically and horizontally offset positions, a plurality of tubular conduits connecting said manifolds with each conduit sloping downwardly and each having a major intermediate zone of constant cross-section and end zones connecting the intermediate zone with the respective manifolds, each end zone being of relatively short length and axially alined with the intermediate zone axis, the cross-sectional area of each end zone decreasing in the direction I of the manifold to which it is connected to there by form a tapering entrance and exit for the in termediate zone, whereby the entering material for the intermediate zone is spread by the entering tapered zone to provide a content of relatively small depth to thereby traverse the major zone under substantially uniform cross section stream form with the depth of the stream determined by the tapered exit zone leading to the lower manifold, each conduit having a substantially greater transverse cross-sectional area than a similar area of the upper manifold, and means for producing a sub-atmospheric pressure in said conduits.

2. Apparatus as in claim 1 characterized in that each conduit cross sectionally is of circular contour to thereby present a cross section of the content of the intermediate zone as having the contour of the segment of a circle.

HENRY VON KOHORN. RALPH S. VON KOHORN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,357,947 Borzykowski Nov. 9, 1920 1,877,337 Kampf et a1 Sept. 13, 1932 1,895,192 Kampf Jan. 24, 1933 2,005,811 Steimmig June 25, 1935 2,020,250 Stephens Nov. 5, 1935 2,087,016 Bradshaw et a1 July 13, 1937 2,146,532 Crane et a1 Feb. 7, 1939 2,355,057 Copeland Aug. 8, 1944 FOREIGN PATENTS Number Country Date 700,710 France Jan. 2, 1931