GB2376025A

GB2376025A - Method of and apparatus for dyeing a fabric

Info

Publication number: GB2376025A
Application number: GB0113378A
Authority: GB
Inventors: Tak Ming William Tsui; Sou Lam Fong
Original assignee: Falmer Investments Ltd
Current assignee: Falmer Investments Ltd
Priority date: 2001-06-01
Filing date: 2001-06-01
Publication date: 2002-12-04
Anticipated expiration: 2021-06-01
Also published as: GB0113378D0; CN1200162C; HK1048146A1; CN1389615A; HK1048146B; GB2376025B

Abstract

The present invention provides a dyeing machine for dyeing a fabric rope, comprising a housing 4 containing a fabric trough 8, a first roller 16 located within the fabric trough 8, a second roller 18 located substantially outside the fabric trough 8, and a drive reel 10 located above the first roller 16 and above the second roller 18, the first roller 16, second roller 18 and drive reel 10 being arranged such that, in use in a first mode a fabric rope is guided through the fabric trough 8, and in use in a second mode the fabric rope bypasses the fabric trough 8.

Description

METHOD OF AND APPARATUS FOR DYEING A FABRIC The present invention relates to a method of and apparatus for dyeing a fabric rope, in particular, although not exclusively to jet dyeing machines for dyeing a fabric rope.

Fabric rope is a width of fabric that is compressed and twisted into a rope-like section. Dye liquor or dyestuff is a mixture of water and dye chemicals, which together form a water based solution.

A jet dyeing machine is a device used for dyeing batches of fabric rope. The term jet refers to a device within the jet dyeing machine that provides some of the motive force to impart a linear velocity to the fabric rope. The same jet may also be used to inject dye liquor into and onto the fabric rope. The term dyeing is the process by which dye is introduced into the fabric rope.

A jet dyeing machine operates according to two basic functions ; a continuously moving fabric rope and a continuously circulating dye liquor. The jet dyeing machine is first loaded with fabric, generally many hundreds of meters, compressed into a fabric rope. The two ends of the fabric rope are joined together to form a continuous rope, which is circulated continuously within the machine.

A conventional jet dyeing machine may comprise a main driving reel, for circulating the fabric rope in the machine, a nozzle and a fabric chamber, over or through which the fabric rope is directed. The nozzle serves two purposes. Firstly, to provide a motive force for the fabric rope and, secondly, to introduce dye liquor onto and into the fabric rope.

Dyeing can be uneven and slow, particularly for medium-heavy weight fabrics. Fibres on the external surface of the rope that are contacted first by the dye liquor are exposed to the concentrated dye liquor. If the dye is permitted to"strike"on the outside of the fabric rope only it may take a long time for the concentration level to equalise in the mass of fibre. Equalisation of the dye concentration throughout the fabric will

eventually occur as a result of a process called"migration". During migration dye in the more concentrated regions will move back into the dye liquor as the concentration of the dye liquor decreases and thus moves into the fibres which have absorbed lower amounts of dye.

Temperature will also affect absorption of many dyestuffs. Raising the temperature while accelerating the dyeing process may also increase initial unevenness of dye uptake, which will, in turn, increase the amount of migration required to level out the dye concentration throughout the fabric. The time required for migration is generally many times greater than the time required for mere application of the dye liquor.

The process requirements for dyeing lightweight and heavy fabrics can differ, because the ease of penetration of dye liquor into the fabric rope will vary depending upon the weight of the fabric. Apparatus suitable for dyeing lightweight fabric rope may not always be as effective when used for dyeing heavier weight fabric rope.

It is an object of preferred embodiments of the present invention to provide an improved apparatus for and method of dyeing fabric rope.

The present invention provides a dyeing machine for dyeing a fabric rope, comprising a housing containing a fabric trough, a first roller located within the fabric trough, a second roller located substantially outside the fabric trough, and a drive reel located above the first roller and above the second roller, the first roller, second roller and drive reel being arranged such that, in use in a first mode a fabric rope is guided through the fabric trough, and in use in a second mode the fabric rope bypasses the fabric trough.

In use of the dyeing machine of the present invention, the fabric trough suitably contains dye liquor. When in use in the first mode, the first roller is suitably submerged, at least in part, and preferably substantially wholly, in the dye liquor.

When the dyeing machine is in use in the second mode, the fabric trough need not contain dye liquor.

The dyeing machine is suitably a jet-dyeing machine. The housing is preferably a pressure vessel.

The dyeing machine suitably comprises an air jet nozzle, which is designed to inject air, preferably at high velocity, uniformly around the circumference and into the body of the moving fabric rope. The air jet nozzle is suitably located downstream of the driven reel.

The first roller and the second roller are suitably a non-driven rollers, or free rollers.

Rotation of a non-driven roller is generally effected by the friction of the fabric rope as it passes over the roller.

The dyeing machine suitably further includes a fabric chamber. The fabric chamber is suitably located towards the bottom the housing. The fabric chamber suitably comprises a metal container with perforated holes having a fabric inlet and a fabric outlet. Suitably, the fabric chamber is a substantially tube-like container. Suitably, the perforation holes are located in the lower surface of the fabric chamber. In use, the fabric chamber is suitably flooded with dye liquor. The fabric chamber is suitably a separate container that is supported above the bottom of the housing of the dyeing machine.

The driven reel is used, preferably in combination with an air jet nozzle, to move the fabric rope through the machine. Suitably, the driven reel comprises a rotating open cage the outside surface of which is composed of evenly spaced rectangular sections arranged around the circumference. In use, the fabric rope is wrapped around the driven reel while an external device provides continuous rotation of the reel. Suitably, the driven reel is located above the fabric chamber. The driven reel is suitably located above the fabric trough. Preferably, the driven reel is located towards the top of the housing.

The fabric trough suitably comprises a metal container. The fabric trough is suitably located above the fabric chamber, preferably, between the driven reel and the fabric chamber. Suitably, the fabric trough is located approximately half way between the driven reel and the bottom of the fabric chamber. Suitably, the fabric trough is located closer to the fabric outlet than the fabric inlet of the fabric chamber. Advantageously, the fabric trough is located substantially adjacent to the fabric outlet of the fabric chamber.

The second roller is suitably located above the first roller. The second roller is preferably located above the fabric trough. The second roller is preferably located to the side of the fabric trough. The second roller is suitably located at the side of the fabric trough that is closest to the fabric outlet of the fabric chamber.

When in use in the first mode, the second roller is suitably arranged to guide the fabric rope between the fabric outlet of the fabric chamber and the first roller located in the fabric trough. Such an arrangement provides for submerging the fabric rope in the dye liquor twice during a cycle through the machine and is particularly suited for medium to heavy weight fabrics.

When is use in the second mode, the second roller is suitably used to guide the fabric rope from the fabric outlet of the fabric chamber directly to the driven reel, thereby bypassing the intermediate fabric trough. This arrangement is particularly suited for lightweight materials and materials that require submerging only once in the dye liquor during a cycle through the machine.

The presence of a second roller helps to reduce the tension in the fabric rope between the fabric outlet of the fabric chamber and the driven reel. When arranged to dye a heavier weight fabric, the arrangement of the first and second rollers break the journey of the fabric rope from the fabric outlet of the fabric chamber to the driven reel into two stages, thus reducing the tension effects compared to that which would be experienced in one long stage from the fabric outlet to the driven reel. For lighter fabrics the tension effects associated with a single stage from the fabric chamber to the

driven reel are not as significant. Therefore, passing the fabric rope around only the second non-driven roller in this case is sufficient to reduce the tension.

The dyeing machine may also comprise a disengaging device to promote removal of excess fluid from the fabric rope, in use. Suitably, the disengaging device is located downstream of the exit from the air jet nozzle. The disengaging device may remove excess fluid from the fabric rope by any suitable method, for example, the disengaging device may move from side to side with a reciprocating movement thereby shaking excess fluid from the fabric rope in use.

Suitably, a dyeing machine according to the present invention comprises a plaiting device located substantially adjacent, and preferably above, a fabric inlet of a fabric chamber. Any suitable plaiting device may be used. Suitably, the plaiting device comprises a transversely reciprocating element that effects two-fold plating of the fabric rope into the fabric chamber. A single device may achieve both disengaging and plaiting functions.

The dyeing machine may comprise a fluid nozzle arranged to inject fluid or dye liquor, preferably at high velocity, around the circumference and into the body of the fabric rope. A fluid nozzle has the dual function of applying dye liquor to the fabric rope and driving the fabric rope through the dyeing machine.

Alternatively, or in addition, a dyeing machine in accordance with the present invention may comprise one or more sprays for spraying dye liquor onto the fabric rope. Suitably, the sprays are located around the fabric trough. Preferably, the one or more sprays are located above the fabric trough. One or more sprays may be located between the first roller and the second roller. One or more sprays may be located between the second roller and the driven reel.

The sprays are used to apply dye liquor to the fabric rope and do not significantly affect the motion of the fabric rope through the dyeing machine. When used in

conjunction with other motive means, such as an air jet nozzle and/or a drive reel, one or more sprays may be used as an alternative to a fluid nozzle.

The dyeing machine may further comprise a collector section to collect the dye liquor that has been sprayed onto the moving fabric rope. The collector may also channel fluid from the disengaging device, the trough and/or the sprays and direct it to a central channel. The dye liquor is then suitably directed to a circulation pump and recycled.

The dyeing machine may also comprise a heat exchanger associated with the circulation pump.

In use of a dyeing machine in accordance with the present invention in the first mode for normal to heavy weight fabrics, the fabric rope is pulled from the fabric chamber around the second roller, around the first roller and through the intermediate fabric trough, around the driven reel, through the air jet nozzle, through the disengaging section and finally plaited into the fabric chamber filled with dye liquor.

In use of a dyeing machine in accordance with the present invention in the second mode for lightweight fabrics, the fabric rope is pulled from the fabric chamber around the second roller, around the driven reel, through the air jet nozzle, through the disengaging section and finally plaited into the fabric chamber filled with dye liquor.

In both cases, the dye liquor is circulated between the collector and the housing by the circulating pump, and up to the one or more sprays located around the intermediate fabric trough. The circulated dye liquor may pass through a heat exchanger, preferably before supply to the one or more sprays.

The present invention advantageously provides a dyeing machine that can be arranged to operate optimally for both lightweight and medium to heavy weight fabrics. The use of an intermediate fabric trough gives medium to heavy weight fabric rope a second stage wherein dye liquor can be introduced into the fabric rope. By using the intermediate fabric trough, the volume of liquor used in the fabric chamber can be

reduced and the clean liquor from the spray section can be more easily recycled. The net result is that the liquor ratio, i. e. the weight of liquor required for a set weight of loading of fabric, is reduced.

Advantageously, the air jet is able to drive the fabric rope at a much higher velocity than a conventional fluid jet. Furthermore, the capacity of the dyeing machine can advantageously be increased because the linear speed of the fabric rope can be increased.

The present invention will now be described, by way of example only, with reference to Figure 1, which is a schematic cross-sectional side view of a dyeing machine.

Figure 1 illustrates a jet dyeing machine 2 comprising a pressure vessel 4, providing a housing, which pressure vessel 4 contains a fabric chamber 6 located in the bottom of the housing 4, a fabric trough 8 located above the fabric chamber 6, in the region of a fabric outlet of the fabric chamber 6, a drive reel 10 located towards the top of the housing 4, an air jet nozzle 12 located downstream of the drive reel 10 and a disengaging device 14 located down stream of the air jet nozzle 12. The dyeing machine 2 further comprises a first roller 16, located within the fabric trough 8. An second roller 18 is located about the fabric outlet 20 of the fabric chamber 6 and above the first roller 16 and the fabric trough 8.

As can be seen from figure 1, the driven reel 10 is located above the first roller 16 and above the second roller 18. The intermediate fabric trough 8 is located about halfway between the driven reel 10 and the bottom of the fabric chamber 6.

The driven reel 10 is arranged such that the fabric rope flows easily into the air jet nozzle 12 during use.

The disengaging device 14 comprises a transversely reciprocating element as shown in the figure by dashed lines, that effects plaiting of the fabric rope into the fabric inlet 22 of the fabric chamber 6, as illustrated.

The machine 2 further comprises sprays 24 adjacent the fabric trough 8 and a spray 26 between the second roller 18 and the driven reel 10.

In use of the machine 2, the fabric rope 28 is driven around the machine by means of the driven reel 10 and the air jet nozzle 12. The fabric rope 28 exits the air jet nozzle 12 and passes over the disengaging device 14, which disengaging device 14 removes excess fluid from the rope 28. The fabric rope 28 is plaited into the fabric chamber 6 by the reciprocating motion of the disengaging device 14.

The fabric rope 28 is drawn out of the fabric outlet 20 of the fabric chamber 6 by the pulling force of the drive reel 10. The fabric rope is guided over the second roller 18.

If the fabric rope comprises a normal to heavy weight fabric, the rope 28 is guided from the second roller 18, around the first roller 16 in the fabric trough 8 and up to the drive roller 10.

If the fabric rope 28 comprises a light weight fabric, the rope 28 passes directly over the second roller 28 to the drive roller 10.

Claims

CLAIMS 1. A dyeing machine for dyeing a fabric rope, comprising a housing containing a fabric trough, a first roller located within the fabric trough, a second roller located substantially outside the fabric trough, and a drive reel located above the first roller and above the second roller, the first roller, second roller and drive reel being arranged such that, in use in a first mode a fabric rope is guided through the fabric trough, and in use in a second mode the fabric rope bypasses the fabric trough.
2. A dyeing machine according to claim 1, comprising a fabric chamber having a fabric inlet and a fabric outlet, the fabric trough being located in the region of the fabric outlet of the fabric chamber.
3. A dyeing machine according to claim 1 or 2, wherein the second roller is located above the first roller.
4. A dyeing machine according to claim 1,2 or 3, wherein the second roller is located above the fabric trough.
5. A dyeing machine according to any one of the preceding claims, further comprising an air-jet nozzle, located downstream of the drive reel.
6. A dyeing machine according to any one of the preceding claims, comprising a disengaging device located downstream of the air-jet nozzle, arranged to remove excess fluid from the fabric rope.
7. A dyeing machine according to any one of the preceding claims comprising a fabric plaiting device.
8. A dyeing machine according to claim 7, wherein the fabric plaiting device comprises a reciprocating element.

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9. A dyeing machine according to claim 7 or 8, wherein the fabric plaiting device and the disengaging device are part of the same device.
10. A dyeing machine according to any one of the preceding claims, comprising one or more sprays for spraying dye liquor onto the fabric rope.
11. A dyeing machine according to claim 10, wherein the one or more sprays are located around the intermediate fabric trough.
12. A dyeing machine according to claim 10 or 11, wherein the one or more sprays are located between the second roller and the first roller.
13. A dyeing machine according to claim 10,11 or 12 wherein the one or more sprays are located between the second roller and the drive reel.