GB2052581A

GB2052581A - Dye fixation

Info

Publication number: GB2052581A
Application number: GB7922215A
Authority: GB
Original assignee: Dawson International PLC
Current assignee: Dawson International PLC
Priority date: 1979-06-26
Filing date: 1979-06-26
Publication date: 1981-01-28
Also published as: GB2052581B

Abstract

Dyes and other chemicals in textile fibres in which the fibres are fixed by exposure to a radio frequency energy field whilst being intermittently fed along a tube (9) by a piston (12). The outlet end (9b) of the tube (9) has a cross-sectional area which is less than that of its inlet end (9a) so as to constrain an increase in pressure within the tube. This rise in pressure and also a rise in temperature in the tube promotes accelerated fixation of the dye or other chemical in the fibres. <IMAGE>

Description

SPECIFICATION Dye fixation process and apparatus This invention reiates to the fixation of dyes and other chemicals in textile fibres by subjecting the treated fibres to radio fequency heat energy of the order of 27.12 MHz, it having already been proposed to use radio frequency generating apparatus for the heat setting of textile fabrics whilst held stationary between pressure applying elements.

The Applicant has already proposed a process for the fixation of dyes and other chemicals in textile fibres, however formed or combined, which comprises continuously conveying, by means of conveyor belts, fibres which have been wetted with dye or other chemical substance through a closely confining tube located between electrodes by which a radio frequency energy field is created in the tube.

In accordance with the present invention however a process for the fixation of dyes and other chemicals in textile fibres, however formed or combined, comprises intermittently feeding fibres which have been wetted with dye or other chemical substance through a closely confining tube of which the outlet end is of lesser crosssection than the inlet end located between electrodes by which a radio frequency energy field is created in the tube, the packing of the tube being sufficiently dense as to ensure that when heated by the energy field the tube and its contents form a partially self-sealing pressure chamber whereby the rate of reaction of the dye or chemical on the fibres is accelerated.

The invention also provides apparatus for the performance of the process as above defined comprising a casing containing radio frequency heating electrodes, a tube of non-lossy material located within or between the electrodes and of which the outlet end is of lesser cross-section than the inlet end, and means located at the inlet end of the tube for ramming into and along the tube batches of textile material supplied by feed means to the inlet end of the tube.

The process can be performed on fibres in the forms of loose aggregate, tops, slubbing, to, yarn and fabrics -- whether knitted, woven, needled.

sprayed and so forth - for instance carpets.

The accompanying drawing shows in schematic side elevation a particular and at present preferred form of apparatus for use in the 'performance of the invention.

Referring now to the drawing there is shown mounted on a base 1 a dye padder unit 2 and a radio frequency heating unit 3. This radio frequency unit comprises two 27.12 MHz radio frequency generators 4 and 5 which respectiveiy supply energy to cylindrical electrodes 6 and 7 situated in a casing 8.

Extending through the casing 8 is a treatment tube 9 made of non-lossy material such as glass or polypropylene. The tube 9, which may be of 30 cm inside diameter and 600 cm in length, has a radial inlet passage 9a for receiving textile material delivered from the dye padder unit by way of an upwardly inclined feed conveyor 10.

The tube 9 has a tapered outlet end 9b and there may be provided an arrangement (not shown) for varying the cross-section of the tube outlet. One such an arrangement could be an iris diaphragm type device or a series of interchangeably mountable plates having orifices of different size. Alternatively the outlet end of the tube could be closed by a spring-loaded flap. The object of all these arrangements is to constrain the outlet of the textile fibre from the tube.

For causing movement of batches of textile material from the inlet end to the outlet end of the tube there is provided at the inlet end of the tube an assembly comprising a ram 11 and a stainless steel piston 12.

In operation textile fibres deposited into the inlet opening are pushed along the tube by operation of the ram and piston assembly. The textile fibres which are in a wet state are heated by operation of the dielectric field created by the electrodes. Moreover due to the close packing of the fibres due at ieast in part to the constraint imposed by the reduced cross-sectional area of the outlet end of the tube a pressure develops within the tube. This pressure accelerates the rate of fixation of the dye. A temperature of approximately 1 300C is obtained in the tube and in conjunction with the pressure effect enables the fixation of dye to be accelerated for all known textile fibres.

The quantity of fibre remaining in the tube when feeding in a batch is completed is removed by hand or by an increased stroke of the piston.

Upward tilting of the tube as shown facilitates cleaning of the tube using a hose pipe.

An advantage of the apparatus as described .compared with previously known apparatus incorporating belt driving means for continuously conveying fibre through the tube is that it occupies a smaller fioor area due to the possibility of achieving a higher packing density of fibre. A typical overall length would be 860 cms.

Approximate packing densities may be as much as 4 to 5 times those obtained with a continuous throughput belt fed machine.

Another advantage is that the apparatus admits of the possibility of varying the amount of textile fibres fed to the machine. Thus slugs of wool or other fibre of 20/30 Kgs weight may be fed through the machine whereas it was a characteristic of apparatus having conveyor belts for feeding fibres through the tube that there was only one practical rate of throughput. As a consequence the process and apparatus in accordance with the present invention is considered to be more economical both from the point of view of capital expenditure and running costs.

1. A process for the fixation of dyes and other chemicals in textile fibres, however formed or combined, comprising intermittently feeding

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Dye fixation process and apparatus This invention reiates to the fixation of dyes and other chemicals in textile fibres by subjecting the treated fibres to radio fequency heat energy of the order of 27.12 MHz, it having already been proposed to use radio frequency generating apparatus for the heat setting of textile fabrics whilst held stationary between pressure applying elements. The Applicant has already proposed a process for the fixation of dyes and other chemicals in textile fibres, however formed or combined, which comprises continuously conveying, by means of conveyor belts, fibres which have been wetted with dye or other chemical substance through a closely confining tube located between electrodes by which a radio frequency energy field is created in the tube. In accordance with the present invention however a process for the fixation of dyes and other chemicals in textile fibres, however formed or combined, comprises intermittently feeding fibres which have been wetted with dye or other chemical substance through a closely confining tube of which the outlet end is of lesser crosssection than the inlet end located between electrodes by which a radio frequency energy field is created in the tube, the packing of the tube being sufficiently dense as to ensure that when heated by the energy field the tube and its contents form a partially self-sealing pressure chamber whereby the rate of reaction of the dye or chemical on the fibres is accelerated. The invention also provides apparatus for the performance of the process as above defined comprising a casing containing radio frequency heating electrodes, a tube of non-lossy material located within or between the electrodes and of which the outlet end is of lesser cross-section than the inlet end, and means located at the inlet end of the tube for ramming into and along the tube batches of textile material supplied by feed means to the inlet end of the tube. The process can be performed on fibres in the forms of loose aggregate, tops, slubbing, to, yarn and fabrics -- whether knitted, woven, needled. sprayed and so forth - for instance carpets. The accompanying drawing shows in schematic side elevation a particular and at present preferred form of apparatus for use in the 'performance of the invention. Referring now to the drawing there is shown mounted on a base 1 a dye padder unit 2 and a radio frequency heating unit 3. This radio frequency unit comprises two 27.12 MHz radio frequency generators 4 and 5 which respectiveiy supply energy to cylindrical electrodes 6 and 7 situated in a casing 8. Extending through the casing 8 is a treatment tube 9 made of non-lossy material such as glass or polypropylene. The tube 9, which may be of 30 cm inside diameter and 600 cm in length, has a radial inlet passage 9a for receiving textile material delivered from the dye padder unit by way of an upwardly inclined feed conveyor 10. The tube 9 has a tapered outlet end 9b and there may be provided an arrangement (not shown) for varying the cross-section of the tube outlet. One such an arrangement could be an iris diaphragm type device or a series of interchangeably mountable plates having orifices of different size. Alternatively the outlet end of the tube could be closed by a spring-loaded flap. The object of all these arrangements is to constrain the outlet of the textile fibre from the tube. For causing movement of batches of textile material from the inlet end to the outlet end of the tube there is provided at the inlet end of the tube an assembly comprising a ram 11 and a stainless steel piston 12. In operation textile fibres deposited into the inlet opening are pushed along the tube by operation of the ram and piston assembly. The textile fibres which are in a wet state are heated by operation of the dielectric field created by the electrodes. Moreover due to the close packing of the fibres due at ieast in part to the constraint imposed by the reduced cross-sectional area of the outlet end of the tube a pressure develops within the tube. This pressure accelerates the rate of fixation of the dye. A temperature of approximately 1 300C is obtained in the tube and in conjunction with the pressure effect enables the fixation of dye to be accelerated for all known textile fibres. The quantity of fibre remaining in the tube when feeding in a batch is completed is removed by hand or by an increased stroke of the piston. Upward tilting of the tube as shown facilitates cleaning of the tube using a hose pipe. An advantage of the apparatus as described .compared with previously known apparatus incorporating belt driving means for continuously conveying fibre through the tube is that it occupies a smaller fioor area due to the possibility of achieving a higher packing density of fibre. A typical overall length would be 860 cms. Approximate packing densities may be as much as 4 to 5 times those obtained with a continuous throughput belt fed machine. Another advantage is that the apparatus admits of the possibility of varying the amount of textile fibres fed to the machine. Thus slugs of wool or other fibre of 20/30 Kgs weight may be fed through the machine whereas it was a characteristic of apparatus having conveyor belts for feeding fibres through the tube that there was only one practical rate of throughput. As a consequence the process and apparatus in accordance with the present invention is considered to be more economical both from the point of view of capital expenditure and running costs. CLAIMS

1. A process for the fixation of dyes and other chemicals in textile fibres, however formed or combined, comprising intermittently feeding batches of fibres which have been wetted with dye or other chemical substance through a closely confining tube, of which the outlet end is of lesser cross-section than the inlet end, located within electrodes by which a radio frequency energy field is created in the tube, the packing of the tube being sufficiently dense as to ensure that when heated by the energy field the tube and its contents form a partially self-sealing pressure chamber whereby the rate of reaction of the dye or chemical on the fibres is accelerated.

2. Apparatus for performing the process claimed in claim 1 comprising a casing containing radio frequency heating electrodes, which are concentric with respect to a tube of non-lossy material exposed to the energy field of the electrodes and of which the outlet end tapers so as to be of lesser cross-section than the remainder of the tube, and a ram and piston located at the inlet end of the tube for ramming into and along the tube batches of textile material supplied by feed means to the inlet end of the tube.

2. Apparatus for performing the process claimed in claim 1 comprising a casing containing radio frequency heating electrodes, a tube of nonlossy material exposed to the energy field of the alectrodes and of which the outlet end is of lesser cross-section than the inlet end, and means located at the inlet end of the tube for ramming into and along the tube batches of textile material supplied by feed means to the inlet end of the tube.

3. Apparatus as claimed in claim 2 in which the area of cross-section of the outlet end of the tube is variable.

4. Apparatus as claimed in claim 2 or claim 3 in which the tube is cylindrical and concentrically surrounded by the electrodes.

5. Apparatus as claimed in claim 2, 3 or 4 in which the tube slopes upwardly from its inlet end to its outlet end.

6. Apparatus as claimed in any of claims 2 to 5 including a dye padder and an endless belt for transferring textile material from the dye padderto a radial inlet to the tube.

7. Apparatus as claimed in any of claims 3 to 6 wherein the area of cross-section of the outlet end of the tube is variable by operation of an iris diaphragm device.

8. Apparatus as claimed in any of claims 3 to 6 wherein the area of cross-section of the outlet end of the tube is variable by a series of interchangeable plates having orifices of different size.

9. Apparatus as claimed in any of claims 2 to 6 wherein the outlet end of the tube is closed by a spring loaded flap.

10. A process for the fixation of dyes and other chemicals in textile fibres substantially as hereinbefore described.

11. Apparatus for the performance of a process as claimed in Claim 10 substantially as hereinbefore described with reference to, and as shown in, the accompanying drawing.

New claims or amendments to claims filed on 6th October 1980.

Superseded claims 1, 2 and 4.

New or amended claims: Original claims 5 to 11 renumbered as 4 to 18 respectively and appendices corrected.

1. A process for the fixation of dyes and other chemicals in textile fibres, however formed or combined, comprising intermittently feeding, by means of a ram and piston, batches of fibres which have been wetted with dye or other chemical substance through a closely confining tube, of which the outlet end tapers so as to be of lesser cross-section than the remainder of the tube, located within concentrically situated electrodes by which a radio frequency energy field is created in the tube, the packing of the tube being sufficiently dense as to ensure that when heated by the energy field the tube and its contents form a partially self-sealing pressure chamber whereby the rate of reaction of the dye or chemical on the fibres is accelerated.