US2632323A - Production of viscose rayon threads, fibers, filaments, and the like - Google Patents

Description

March 24, 1953 H. B. MERRIMAN 2,632,323

PRODUCTION OF VISCOSE RAYON THREADS, FIBERS, FILAMENTS AND THE LIKE Filed Jan. 9, 1952 2 SHEETS-SHEET 1 F|G.l.

OX 1 S.

/N VE/VTOR Horace Barf/eff Men/man By his af/omeys FILAMENTS March 24, 1953 H. B. MERRIMAN PRODUCTION OF VISC OSE RAYON THREADS, FIBERS,

AND THE LIKE 2 5HEETSSHEET 2 Filed Jan. 9, 1952 4 INVENTOR Horace BarfiefiMerr/man By his attorneys Patented Mar. 24, 1953 PRODUCTION OF VISCOSE RAYON THREADS, FEERS, FILAMENTS, AND THE LIKE Horace Bartlett Merriman, New Malden, England,

assignor to Courtaulds Limited, London, England, a British company Application January 9, 1952, Serial No. 265,677

In Great Britain January 23, 1951 1 Claim. 01. 68-209 This invention relates to the production of viscose rayon threads, fibres, filaments, and the like continuous filamentary materials hereinafter generally referred to as threads, and is particularly concerned with the recovery of carbon disulphide from such threads during their manufacture. The term thread also includes thick tows of filaments such as are normally built up for the production of staple fibres.

In the spinning of viscose the acid coagulant bath decomposes a large percentage of the Xanthate residues present in the viscose to carbon disulphide which is carried over by the thread to subsequent processing stages. Proposals have already been made for recovering such carbon disulphide from the threads. Thus British Patent Specification No. 170,817 describes a process in which the carbon disulphide is evaporated from the thread by passing it through a hot water bath beneath a canopy, the edges of which are immersed in the hot water so that the liberated vapours may be collected by a pipe and liquefied. In United States patent specification No. 2,451,890 it is proposed to pass the thread through a tank of hot water under a bell-like cover, the edges of which are immersed in the liquid and to collect the vapours under their oWn pressure, the

thread continuously entering the tank at one end and leaving it at the other end after having been conveyed progressively through the bath over rollers, plates or between perforated partitions, beneath the bell-like cover.

It is known that carbon disulphide vapour and air form an explosive mixture. Carbon disulphide vapour is also highly objectionable to operatives so that it should not be allowed to escape and pollute the atmosphere of the spinning shop. Prior proposals for carbon disulphide recovery have not been entirely satisfactory from these points of view.

The object of the present invention is to facilitate the threading up of a carbon disulphide recovery plant.

In accordance with the present invention, apparatus for the recovery of carbon disulphide from viscose rayon threads comprises a container for a heated liquid which is fitted with a continuous channel around its upper edge, also for containing a liquid, a bell mounted over the container so that it can be raised and lowered and so that, when in its lowest position, its edges will be immersed in liquid in the continuous channel to seal off the container, the bell having thread entrance and thread-exit ducts so constructed that when the bell is in its lowest position the lower edges of the ducts are immersed in the heated liquid in the container and the ducts are.

thereby sealed off, conveying mechanism fitted to the bell for passing the thread through the container and means for withdrawing carbon disullected from godets and the like and known generally as channel liquor.

The conveying mechanism preferably consists of two groups of freely-mounted or stationary rollers with their axes parallel and one group at Threads when treated each end of the bell. with hot liquid may tend to shrink and the use of freely mounted rollers ensures that their rota tion is effected solely by the travelling thread and, as a result, the thread is not submitted to any undue tension or strain during the hot liquid treatment.

In a preferred form of apparatus, two threads" are treated simultaneously by using a large tank having a continuous peripheral channel and. a central channel, joined at its ends with the peripheral channel, dividing the tank into two recovery zones. The central channel preferably has a partition attached to it to assist in dividing off the two recovery zones. Each of the two zones has its own bell, conveying mechanism and plant for removing and recovering carbon disulphide from within the bell.

A specific example of an apparatus constructed in accordance with the present invention is illustrated in the accompanying drawings, in which,

Figure 1 is a plan view showing a single bath comprising two recovery units, the bell of one unit being removed to show details within the tank,

Figure 2 is a section through line 22 of Figure 1, and

Figure 3 is a section through line 33 of Figure 1.

Referring to the drawings, a trapezoidal tank i has a continuous channel 2 around its periphery and is divided down its centre by a similar channel 3, connected at its ends to the channel 2. A vertical partition 1 extends downwardly from the channel 3 for about half the depth of the tank i. The tank i is thus divided into two identical recovery units 5, 5 each of which has a continuous channel surrounding its periphery, the channel 3 being common to both units. In operation, the tank I is nearly filled with hot water or other liquid supplied from pipes I, 8 while the channels 2, 3 are filled with a cold liquid. In the following description, only unit 5 will be described in detail but it will be understood that unit,6 is constructed in thesame Way and like numerals are, included in the; drawings to indicate like parts.

A hell 9, which completely covers the unit 5, has.

a peripheral lip I6, which, when fitted into the liquid in the channels 2, 3 as SIIOWIL'fOIIHS ages"- tight seal. The bell 9 can be raisedFandflowered, for example, by an overhead .crane 28 hookedintO- eyes 26, 21. The bell 9 has afunnel-shaped open: ing I I and a similarly shaped open'ing'I 2 bywhich the tow enters and leaves respectively, the recovery unit; both openings I I, I2 are wide'enough-pto' admit the hand. In operation, the= loweredfges of the openings II, I2 are both immersed-in: the liquid in the tank I so that the openings are also sealedofih Twosets of fixed dollies or rollers I3 miarelsusnendedifrom the underside ,.of the bell; {by .two holders I &A, IAA closeto .the:p enings ["LJZ'respectively. Thei'belll also has a trap 24. inlwhich; carbon disulphide vapours collect and. are drawn awayjthrougha pipeZBto a: recovery plant .(not shown) Thennit ,5isoperated as follows i'IYo-start up, jthetbell"9f is raised anda tow I of freshly-extruded viscose filaments is passed-by handthrough, theeopenin'g I'l; round the rollers: l3, I4 as shown particularly in Figure 1, and then out throughthe opening I21 The bell9 is' nowlowered' on to; the tank I' so that the tow I5Iis11immersedih the liquid in thetank, the pe ripheral edge U ofithefbelljis immersed" in the channels 23.3,to58al1off the bell'and' the lower edgesofstheiopenings, I I V I 21are immersed in the liqmddnlthe. tank'tosealfloff these openings. At the entranoeend; theltow, l 5passes over a, roller Ifi'gintosthe bathandlatl the exitend it passes over rollers I1, I 8, I9" on its way to the staple fibre.cutterv (not, shown) the rollers- I1; I 8; I 9" serve-,jto, remove excess, liquidifrom .the tow, the excess'lliqnididraininggback into the tank through the. opening. I2.. As; the; towpasses through. theghot liquid carbondisulphide associated f,WiIJh 7 itisyapourized;,collectedi in thegtrapjd andjreicovered by way of the pipe any bubbles of gas formed near the openings II, I2 are directed towards the centre of the tank I by guides 20, 2| which are provided with slots 22, 23 respectively to allow passage of the tow I5. If desired a lid may b'explacedtover the ztank il during tl'ie settingup operation.

With the machine according to the invention, the sealingof the bell during passage of the tow remains,unbroken sothat there is no mixture ofiairrand'barbonzdisulphide vapour formed during actual recovery operations.

Whatlclaim is:

Apparatus; for: the simultaneous recovery of carbon disulphide from two viscose rayon threads comprising acontainer for a heated liquid, a con- A trance and threadexitducts within the saidbells.-

so constructed that when the bellsare intheir lowestpositions the lower edges ofj'th'e ductswillf be immersed in theheatedfliquid in .the.container; Wherebythe ducts are sealed ofi, conveyingmeche anism .fitted .to .-the inside, of said bellslfor passing;

' two threads through the container, and, means:

Name Date- Ufnowski Oet. 19, 1948 Number

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