Apparatus For Treating Webs

Abstract

An apparatus for impregnating cloth with, for example a dye liquor in which the cloth is moved past a vacuum chamber which removes the air from the cloth and is then immediately subjected to the action of a dyeing bath. The evacuated cloth either is passed through the dye bath or it is moved past the outlet of a dye bath, the dye being fed gravitationally to the cloth in the latter case. An endless rubber belt ensures that there is no loss of vacuum at the vacuum chamber and assists in moving the cloth past the vacuum chamber and dye bath; the cloth is in direct contact with the vacuum chamber which is not rotated.

Description

This invention relates to apparatus for treating textile and other webs with liquids and/or fluids. Such liquids and/or fluids may be inter alia, bleaching chemicals dyestuffs, and/or finishing compounds.

The present invention is particularly concerned with apparatus for impregnating textile and other webs with such liquids and/or fluids.

Hitherto with conventional methods of impregnation which, for the most part, comprise immersing the web in a tank containing a treating liquid followed by squeezing between a pair of rolls, it has been impossible to obtain the desired complete saturation of the webs by the treating liquid. To assist liquid absorption or pick-up webs have been previously prepared by scouring to render it absorbent. When webs are not properly or uniformly or levelly prepared across the width not only has it been found difficult to force liquor into the web but the degree of absorption of the liquor by the web frequently varies across the width with the result that the appearance of the web is not uniform.

The present invention provides apparatus which increases the absorption of treating liquid and/or fluid into webs and in consequence which obviates or mitigates the need for previous scouring and preparation in many cases, and further which ensures at the same time a perfectly uniform or level saturation and therefore uniform or level effect on the web across its width.

According to the present invention there is provided apparatus for use in the impregnation treatment of a textile or other web with a liquid and/or a fluid, the apparatus comprising a vacuum chamber having a slot or other opening past which a web can be moved, an impregnation bath immediately after the vacuum chamber, and an impervious, vacuum-sealing belt, band or the like for moving the web past the vacuum slot in close contact therewith and past or through the impregnating bath.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic view of an impregnating apparatus according to the present invention;

FIG. 2 is a sectional end view of the vacuum chamber and impregnating bath;

FIG. 3 is a plan view of a wearing member providing vacuum slots or openings and impregnating medium outlets;

FIG. 4 is a section on the line IV--IV of FIG. 3;

FIG. 5 is a fragmentary underneath plan view corresponding to FIG. 4;

FIG. 6 shows an example of an entry and exit arrangement for the apparatus;

FIG. 7 is a diagrammatic view of an apparatus according to the invention when it is to be used with solvent liquors;

FIG. 8 is a diagrammatic view of another modified apparatus; and,

FIGS. 9 and 10 are a sectional view and a fragmentary underneath plan view of a modified wearing plate.

Reference is made firstly to FIG. 1 of the drawings.

The apparatus comprises basically a wetting-out unit consisting of a vacuum box 21 and a liquor box 22 serving as an impregnation unit, and a rubber or other elastomeric endless belt 23 impervious to the treating liquor.

The textile web or cloth which is to be impregnated is indicated at 24.

The web 24 is transported through the wetting-out unit between the vacuum box 21 and liquor box 22 and the rubber belt 23. The web 24 which is trapped between the boxes 21 and 22 and the rubber belt 23 passes successively under a vacuum slot and the outlets of the liquor box 22. The web 24 is not subjected to any tension or drag from the suction slot due to the fact that the belt 23 is driven.

It will be manifest that the rubber belt 23 provides an effective seal to obviate or mitigate loss of vacuum.

The suction circuit is indicated by dotted arrows and comprises the vacuum box 21, a high vacuum receiver 25 and a high vacuum pump 26.

The liquor circuit is indicated by full arrows and comprises the liquor box 22, a liquor level trough 27 which, in use, is at the same level as the liquor box 22, a liquor supply tank 28 fed from mixing tanks (not shown) and a drip trough 29.

Pumping traps for the suction and liquor circuits are indicated at 30.

A washing circuit is also provided for the apparatus and is indicated by dot-dash arrows. This circuit uses, say, hot water and serves to wash out the receiver 25, the supply tank 28, the liquid level trough 27 and the liquor box 22 and vacuum box 21.

After impregnation the web 24 is subjected to means for removing excess liquor. Such extraction means may be either a squeezing nip 31 or suction extraction. In the latter case, there is a suction box 32 with an appropriate slot which is connected to a suction receiver 33 and a suction pump 34. The suction box 32 and receiver 33 are connected to the washing circuit.

In either case excess liquor is returned to the storage tank 28.

Any liquor which is drawn into the high vacuum line is trapped and pumped into the storage tank 28.

The abovedescribed apparatus is a recirculatory apparatus. Where the apparatus is to be used with liquors unsuitable for recirculation, the storage tank 28 is omitted and the liquor level trough 27 is fed directly from mixing tanks (not shown). Also drains are provided at locations D, the piping between two of these locations and the drip trough 29 and the trough 27 respectively being omitted.

The wetting-out unit will now be described in greater detail.

The unit comprises a tube 35 closed at its bottom by a high density polyethylene wearing plate 36 and subdivided internally by a partition 37 to define the vacuum box 21 and the impregnation box 22. The tube 35 is closed at one end by a plate (not shown) and at its other end abuts a plate formed with an opening (also not shown).

The vacuum circuit is connected to the vacuum box 21 by convenient piping 48 and the liquor circuit is connected to the impregnation box 22 by convenient piping 49.

The wearing plate 36 is most important and is provided with a series of holes 50 for securing it to the tube 35 by bolts or studs (not shown). The impregnation box outlet is constitutued by an elongate slot 51. This construction ensures that there is uniform application of the treating liquor to the web or cloth 24 thus avoiding "spotting" i.e. non-uniform application of the treating liquor. The suction slot or opening is constituted by two parallel rows of staggered holes 52 with the bottom ends of the holes 52 in each row being connected by an elongate slot 53. The provision of these slots 53 ensure uniform removal of the air from the cloth or web 24 thus avoiding "striping" on the cloth or web.

The spacing between the vacuum holes 52 and slots 53 and the impregnation slot 51 is small, say between one and two inches and preferably one and a half inches. It is important that this distance be as small as possible to ensure that no air or as little air as possible enters the evacuated interstices of the web or cloth 24 before entry of the treating liquor.

In a modified wearing plate (FIGS. 9 and 10) the impregnation box outlet is constituted by a series of holes 86 communicating with an elongate slot 87, while the vacuum or suction slot is constituted by two parallel rows of staggered holes 88 with the bottom ends of the holes 88 in the row adjacent the vacuum holes 86 being connected by an elongate slot 89. The holes 88 in the other row may also be connected by an elongate slot 90.

It is appropriate to mention here that the impervious endless belt 23 passes round two rollers or drum 55 and 56, the roller or drum 56 being driven as hereinafter described and the roller or drum 55 being mounted so as to apply a tension to the belt 23. This mounting may conveniently be a pair of arms carrying the roller 55, the arms being pivotal to effect the tensioning. Alternatively, the roller 55 may be mounted on a slide arrangement.

Various entry and exit arrangements may be used with the apparatus, for example, entry from wagon or batch and exit to plaiter or batch or predryer or other machine.

A convenient but non-limitative entry and exit arrangement is shown in FIG. 6.

The entry arrangement comprises entry rails 65, an entry batch 66, scroll and tracking rolls 67, uncurlers 68, driven openers 69, and cloth guider 70. These entry arrangement components are not all used together but are optional depending on the kind of material being treated.

The exit arrangement comprises a delivery batch 71, a giant batch 72 or a feed 73 to other machines.

In use a web or cloth 24 is fed through the wetting-out unit where it is successively evacuated of air and immediately impregnated with treating liquor as aforesaid, excess moisture being thereafter removed by the suction slot or squeezing nip.

This apparatus allows total saturation or "liquor-logging" of the web or cloth with many advantages, viz:

1. Dyeing -- Levelness and uniformity of shade (in some instances stronger shade than normal padding.)

Freedom from skitteriness or "frostiness". Complete penetration.

Easy impregnation of water-repellent or hydrophobic fibres e.g. synthetic fibres.

Many unscoured fabrics, especially knitted cottons, can be dyed as well as if they had been scoured. (But it is necessary to confirm that size and impurities do not interfere with the dyeing or fixation process).

Elimination of the seam line apparent on circular knit goods pad-dyed conventionally.

2. Bleaching.

By vacuum impregnating the bleach liquor the same degree of whiteness can be obtained with appreciably less chemical (viz. peroxide) and the reaction time reduced. Vacuum impregnation puts the bleach liquor where it is needed-right in the fibre almost instantaneously.

3. Finishing.

The more uniform and more thorough penetration of resin into the fibres improves crease resistance and other such properties.

If the abovedescribed apparatus is used with solvents it is additionally provided (see FIG. 7) with hinged covers 74 and a connection 75 to a solvent evaporator. The cloth feed path is indicated at 76 and the porous drum and rubber belt at 77 and 78 respectively.

An alternative construction of apparatus is diagrammatically shown in FIG. 8 and comprises a vacuum chamber or tube 80 connected to a high vacuum pump (not shown) and having in its wall a vacuum slot 81.

An endless belt 83 of an impervious nature is located ajdacne the vacuum slot 81 with one of its runs passing partially around the vacuum chamber 80 in the region of the vacuum slot 81. This impervious belt 83 forms with the wall of the vacuum chamber 80 upstream of the vacuum slot 81 in the direction of travel of a web 84 an impregnation treating bath 85, for example, a dye bath, appropriate side walls (not shown) for the bath being provided.

This impervious belt 83 is of relatively substantial proportions and is provided with propelling means.

In use, all air is evacuated from the web 84 by passing it past the vacuum slot 81 in the wall of the chamber which is, in turn, almost completely evacuated by the high vacuum pump. The web 84 is trapped as it passes past the slot 81 between the vacuum chamber 80 and the endless belt or band 83 which serves as a seal to prevent loss of vacuum.

After passing the slot 81 and while still evacuated the web 84 is immersed in the liquid with which it is desired it should be impregnated. The web 84 from which all air has been evacuated thoroughly absorbs the liquor immediately. It is only necessary thereafter to remove surplus moisture from the web by either passing the web through a pair of conventional squeeze rollers or over a second slot to which suction is applied to withdraw in this case the surplus moisture which has not been absorbed by the fibres of the web. In the event that such a suction device is used for removing the surplus liquor the surface of the web opposite to the suction slot is open to the air and there is therefore no question of evacuating the web as when passing over the first slot.

The belt 83 need not be endless and the treating bath need not be defined by the vacuum chamber and the impervious belt.

Claims

What is claimed is:

1. Apparatus for use in the impregnation treatment of a web with a fluid comprising vacuum chamber means, slot means formed in said chamber means and having a length at least equal to the width of the web to be impregnated, fluid impervious vacuum-sealing belt means having a width greater than the length of said slot means for supporting and transporting said web, means supporting and driving said web carrying belt means past said slot means in fluid sealing contact with said vacuum chamber means, impregnation bath means disposed contiguously to said vaccum chamber means and said belt means on the downstream side of said chamber means in the direction of travel of said belt means whereby a web carried by said belt means will be subjected to a fluid in said bath means immediately subsequent to being subjected to a vacuum by passage over said slot means.

2. Apparatus as claimed in claim 1 in which said impregnation bath means has an impregnating fluid outlet opening directly on to a web which is being moved past said outlet in close contiguous contact therewith by said vacuum-sealing belt means.

3. Apparatus as claimed in claim 2, in which said slot means and said outlet are disposed closely adjacent to one another.

4. Apparatus as claimed in claim 3, comprising a wearing plate constituting the bottom of said vacuum chamber means and said impregnation bath means and being apertured to provide said slot means and said outlet.

5. Apparatus as claimed in claim 4, in which said outlet is defined by an elongated slot.

6. Apparatus as claimed in claim 5, in which said slot means and the interior of said chamber means are interconnected by a row of holes formed in said wearing plate.

7. Apparatus as claimed in claim 4, in which said slot means is defined by two rows of holes in the wearing plate extending transversely to the direction of travel of said belt means with the holes of one row staggered relative to the holes of the other row and with the bottoms of the holes in one of the rows merging in an elongated slot at their trailing edges in the direction of movement of said belt means, while the holes in the other row merge in an elongated slot at their leading edges in the direction of movement of said belt means.

8. Apparatus as claimed in claim 4, in which said wearing plate is formed of high density polyethylene.

9. Apparatus as claimed in claim 4, in which said wearing plate is substantially arcuate in the region of the vacuum chamber means and impregnation bath means, said belt means being endless and passing around a pair of rollers positioned at opposite ends of said plate to constrain said belt means to travel in an arcuate path over said wearing plate, means movably mounting one of said rollers for tensioning said belt while the other of said rollers is driven.

10. Apparatus as claimed in claim 9, comprising prime mover means for driving said driven roller.

11. Apparatus as claimed in claim 1 further comprising recirculatory circuit means including said impregnation bath means, a fluid supply tank connected to the impregnation bath means for feeding a fluid to the impregnation bath means, a fluid level tank also connected to the impregnation bath means to ensure topping up of the latter and a drip trough under the impregnation bath means to collect excess fluid, said impregnation bath means being disposed for gravitational feed of the impregnating fluid to a web passing beneath said bath means.

12. Apparatus as claimed in claim 1 further comprising a high vacuum pump and a high vacuum receiver and means connecting said vacuum chamber means to said high vacuum pump through said high vacuum receiver.

13. Apparatus as claimed in claim 1 further comprising squeezing nip means disposed downstream from said bath means in the direction of travel of said belt means to remove excess fluid from the web.

14. Apparatus as claimed in claim 1 further comprising suction means disposed downstream from said bath means in the direction of travel of said belt means which serves to remove excess fluid from the web.

15. Apparatus as claimed in claim 1 further comprising a closed casing having hinged covers surrounding and enclosing said vacuum sealing belt means, said vacuum chamber means, and said impregnation bath means and means connecting said casing to a solvent extractor.

16. Apparatus as claimed in claim 1 in which said vacuum chamber means is comprised of a vacuum tube having a vacuum slot therein extending transversely of said belt means, said belt means defining with the downstream wall of the vacuum tube the impregnating bath means whereby subsequent to passage over said vacuum a web carried by said belt means will be passed directly through fluid in said impregnating bath means.