IL31193A - A method and apparatus for the wet treatment of fibrous textile materials - Google Patents

Description

τρηπι πο*ΐί> emavna anen ia'a A method and apparatus for the wet treatment of fibrous textile materials LliDVIG SVJv SSON (HOLLAND) N.V, C: 29407 - la - # The present inven ibn relates to the wet treatment of textiles and like materials, including those consisting of or containing synthetic fibres, in bulk or in worked condition, e.g. by way of washing, bleaching, dyeing or the like, in which treatment a liquid and a gas, preferably in a closed circuit, is pressed through tie material.

, In the wet treatment of most t extile materials by known methods it has proven /Impossible to maintain the volume of the material. This is usually losely wound on a perforated cylinder and is treated in a receptacle, for example, an autoclave. During this treatment thi material tends to become paoked too tightly, owing partly to its own weight and partly to the pressure of the treating liquid. A further important point is the strain which will appear in the material during the reeling on the cylinder. If the material is too losely wound, passages form easily in the material through which the liquid flows owing to the smaller resistance therein. If, on the other hand, the material is wound too tightly it will be compressed and a volume expansion, which may be desirable, is prevented. A further disadvantage of this method is the difficulty of removing the air occluded in the material. Larger air bubbles, or clusters of bubbles, stay' in the material and prevent the treating liquid from reaching all fibres therein, so that the dyeing operation produces poorly and irregularly dyed portions.

By a known arrangement the liquid of a dye bath is stirred by jetB of pressurized air in order to move the textile goods in the bath. This arrangement requires large volumes of gas. in order to remove the dirt washing liquid under pressure from the surface of the textile material and even from its interior, and thus to permit clean washing liquid to contact the material. In. this case, too, the volume of steam or gas introduced under •pressure into the washing apparatus must be very large.

The invention has the object to provide a method for the wet''treatment of textile materials which can be carried but efficiently with a smaller volume of pressurized gas.

The invention consists in a method for the v/et treatment, especially dyeing, of textile materials being fibres or tissues or articles made therefrom, possibly reeled on one or several bobbins or the like, wherein the treating liquid is forced b'y means of a pump or. the like, preferably in a closed circuit, through the material and a gas is introduced through one or several nozzles into the treating liquid before the latter reaches the material under such conditions of pressure and rate of flow of the (gas, and flow. of the liquid, that the gas is broken up into very small bubbles at the outlet of the nozzle or nozzles by the flow velocity of the treated liquid and the bubbles are positively carried by the treating liquid through the material and made to penetrate between the fibres, filaments or fibrils of the material and to occupy continuously part of the free space between the latter..

Practical tests have shown that by this method a very •good uniformity of treatment, e.g. dyeing, is attained. With dispersion dyes this result is apparently further enhanced in that the air bubbles act as carriers for the d ©stuff, whereby the surface activity of the dispersants on the particles of the A - 3 - # (mo^r^-effect ) is considerably retarded and a more even and smoother dyeing is obtained. The work is also simplified as fewer working operations are necessary, whin means lower production costs and, last but not least, a reduction in time re-quired.: ■ · ■ :i ':' .

The invention further provides ah apparatus for carrying out the method aforesaid,, which comprises a container designed for receiving th material and provided with a feeder for the treating liquid and at least one feed conduit for the pressurized gas and a gas atomizer including at least one nozzle designed for a gas flow velocity of 100-400 m/sec. in the nozzle. An ,embodiment of an apparatus according to the invention is illustrated, by way of example, in the accompanying diagrammatic drawing.

The apparatus includes a cylindrical container 1 which is an autoclave provided at one end with a removable lid 2. A perforated cylinder 3 is coaxially mounted in the container; it serves ibr winding on it the material 4 to be treated. The cylinder 3 is supported at one end only (see below), and an amiular space is left between the material 4 and the wall of the container. The end of the cylinder 3 remote from the lid 2 is connected through a sealed joint to an,inlet 5 of the container. To this inlet there isjconnected 'έ, conduit 6 whic leads to a pump 7 having a comparatively high capacity. The perforations of cylinder 3 are so located that the perforated zone is completely covered by the material. A return conduit 8 leads from the lower part of the container 1 through a heat exchanger 9 back to the pump. The liquid is forced into the cylinder 3 and through the material 4 and flows 31193 2, 4 back through conduit 8 to the pump 7.

A compressed-air conduit 11 with manometer 12 and reducing valve 13 leads from a source of compressed air to a nozzle 10 arrqnged in the conduit 6 between the pump 7 and inlet 5· T e nozzle 10 has a very small outlet opening and imparts to the air a very high velocity, e.g. up to 100 - 400 meters/sec. It distributes the air, for example, in the form of a cone. The reducing valve 13 maintains in the conduit 11 a pressure of 1 - 5 atmospheres above the static pressure in the autoclave. The capacity of the pump 7 is such that the volume of liquid in the autoclave 1 is replaced 1*5 - 2 times per minute.

To the flow of liquid issuing from the pump 7, very finely subdivided air is continuously added at a rate of, for example, about 0.1 - 10 litres per minute at 20°C and 760 mm Hg for a pumping rate of 10.000.litres o liquid per minute. The air introduced into the liquid is further subdivided and mixed with the liquid by the turbulence, and the chemical compounds contained in the treating liquid have an emulsifying effect οή the air The air has a higher pressure than the liquid and, furthermore, owing to the difference in temperature between the air and liquid the air will expand whereby the bubbles ; are fiblll more subdivided . When the liquid passes through the material the very small air bubbles penetrate the several layers of the material and separate the filaments tereof. , The liquid will hereby have a possibility to act uniformly on the material. Compression of the material is thus avoided and shrinking, if it occurs at all, can occur to desired extent. As the ai bubbles pass continuously through the material the liquid must be s teadily supplied with fresh air. sur ace and is evacuated iri any suitable manner, e.g. through a φ circuit which comprises a conduit 14 which is connected between the upper part of the autoclave and a branch conduit 15, which latter communicates wi1;h a glass tube level indicator 16, and further to the return conduit 8 to the pump 7 through a valve 17 and conduit 18. The evacuation circuit is furthermore connected to an expansion vessel 19 from which a conduit 20 leads through a cooler 21 and valve 22 to the upper part of an open receptacle 23. The valve 17 is open so much only as to set up, owing to the aspiration in tube 8 a state of sub-atmospheric pressure in conduit 18 and the tube 16.

A further pump 24, connected at its aspiration side to receptacle 23 and at its discharge side to the autoclave 1, maintain a static pressure and circulation through the latter. This steady pressure in the autoclave is regulated by means of a valve 25 arranged in a conduit 26 between receptacle 23 and the lower part of the autoclave. A further cooler 27 is included in conduit 26.

The method according to the invention is illustrated, by the following Example concerning the ' dyeing of yarn.

Materials Polyacrylonitrile yam 1/20 Km. (i.e. having a weight of 1 g per 20 m length). Colour: Orange. Weight: 406 kgs material, volume 6f liquor 4500 litres. Working pressure (static pressure in the autoclave): 3.5 atmospheres. Pressure drop of 0.6 atmospheres across the material being penetrated by the treating liquid. Air pressure: 8.5 atmospheres. Nozzle: MLS 1000 (denomination of a specific nozzle of the Ludvig Svensson design) .» about 1200 cm^/min of air. Pump capacity 11,000 litres/min.

The dyeing liquid, containing all the necessary chemicals was heated in a mixing vessel to 75°C Air in finely divided state was supplied to the liquid during the whole dyeing operation. 31193 2 6 - Temgerature Dyestuff in liquid, Time % cf initial amount 0 min. liquid transferred rom the mixing vessel to the apparatus, injection of air ¾egins 75° 100 2 min. heating of the apparatus 4 min. liquid transfer completed min. 100° 70 16.5 min. 102° 60 19.5 min. 102° 55 22 min. 102° 50 24 min. 102° 35 26 min. 102° 20 29 min. 108° 10 31.5 min. 110° 5 33 min. 114° 38 min. cooling 114° 43 min. 100° 48 min* washing 85° '3 min. discharge of the liquid 57 min. treatment finished The method according to the invention has, among others, the following advantages, as compared with conventional methods: a. The addition of air increases the volume of the material to be treated, and as a result the liquid passes with a „ 7 - b. Alternatively, and depending upon the type of material to be treated, .the dyestuff absorption may procCed-Vil a normal rate as in known methods, if the flow velocity is decreased. This will diminish the pressure drop through the material, where^- by the volume and the consistenc of the material will be influenced. Especially with texturized or thermoplastic materials this is important as these materials usually flatten under the influence of the liquid passing through them.. cf By a suitable control of the rate of flow and the size of the air bubbles it is possible to force the liquid from inside a cylinder outwards through the material wound thereon in an intermittent o pulsating' flow whereby the action of the dyer- stuff is prolonged, in that the dyeetuff - carried by air bubbles - flows along the fibres of the material with an intermittent movement, ^ is retarding action is decreased as the size of the body of material increases. d* As the material ie loosened and expanded by the air and thereby becomes more voluminous, the subsequent operations are favourably influenced The time required for washing and drying is considerably decreased., The embodiment of the invention described above by way of example may be modified in many reepects w ithin the scope of this invention.

Thus, for example, the treating vessel may be disposed upright . It need not be an autoclave, and the treatment may be effected at atmospheric pressure. The support for the fibrous material need not be rotatable; and generally the material to be treated indicated above, concern a specific example only and will be changed in accordance with the circumstances of eaoh particular caser

Claims (4)

1. , A method for the wet treatment* especially dyeing, of textile materials being fibres or tissues or articles made therefrom, possibly reeled on one or several bobbins or the like, wherein the t reating liquid is forced by means of a pump or the like, preferably in a closed circuit, through the material and a gas is introduced through one or several nozzles into the treating liquid before the latter reaches the material, under such condi-tions of pressure and rate of flow of the gas, and flow of the liquid, that the gas is broken up into very small bubbles at the outlet. of the nozzle or nozzles by the flow velocity of the treated liquid and the bubble are positively carried by the treating liquid through the material and made to penetrate between the fibres, filaments or fibrils of the material and to ocoupy continuously part of the free space between the latter.

2. A method according to Claim 1, wherein the gas is air.

3. · method according to Claims 1 or 2, wtierein the gas is introduced into the liquid at a volume ratio of about 1:100,000 to 1:1,000, the volume of the gas being calculated as normal volume.

4. A method according to Claim 1, wherein the gas is atomized in the treating liquid. . An apparatus for carrying out the method according to any of Claims 1 to 4* comprising a container designed fl)r reeeiving the material and provided with a feeder for the treating liquid and at least one feed conduit for the pressurized gas, and a gas atomizer including a least one nozzle designed for a gas flow velocity of 100-400 m/sec, in thejaozzle. For the Applicants