GB2060014A - Improvements in or relating to the scouring and milling of textile fabrics - Google Patents

Abstract

In a method of scouring and milling a woven fabric in a combined scouring and milling machine the fabric is wetted out with a soda ash/water liquor, the liquor recovered and the milling operation completed. The recovered liquor is used in the initial part of the scouring operation, the scoured fabric rinsed by spraying with clean hot water using soap/soda ash/water liquor and hot water being discharged to drain. The fabric is then washed to remove residual oils and finally rinsed. With this method, operator handling of the fabric, the soda ash required and the effluent produced are all reduced.

Description

SPECIFICATION Improvements in or relating to the scouring and milling of textile fabrics This invention concerns the scouring and milling of textile fabrics and in particular woollen fabrics.

It is well known that loom state fabrics contain unwanted matter such as the natural oils that are present in the wool fibres, oils that may have been added during the blending and processing of the fibres, and dirt. Basically the scouring process serves to remove the oils and dirt and the milling (or fulling) process serves to consolidate the fabric by causing it to shrink, usually both warp and weft directions, by a predetermined amount.

Traditionally scouring and milling has previously been carried out in different machines, thus the fabric during these processes has been transferred, manually, from machine to machine.

More particularly the scouring and milling (or fulling) processes have, in the past, been carried out in the following manner.

A length of loom state material has been placed in a scouring machine together with a quantity of scouring liquor comprising soda ash and water.

This liquor has been used to saturate the fabric and the soda ash in the liquor dissolves the oils from the fabric as it continuously circulates, in loop and rope form around the machine and between a pair of rollers which, while they apply sufficient pressure to cause the fabric to circulate do not apply high squeezing forces thereto.

Previously the liquor was deposited into the bottom of a trough forming a reservoir in the lower region of the machine. The fabric during its circulation passed through this liquor.

After the initial scouring described above the fabric was rinsed. This step constitutes the spraying onto the fabric of clean hot water while simultaneously removing the oily scouring liquor from the lower region of the machine. Rinsing continued until all of the oily liquor had been removed from the fabric and until the lower region of the machine contained a reservoir of hot water only. During rinsing the fabric was subjected to squeezing action between the rollers referred to above.

At the end of this process the original scouring liquor had all passed to waste.

The next step consisted of introducing a soap plus soda ash liquor into the machine further to wash and clean the fabric. The soap content of the liquor was either mineral or vegetable soap.

During this step of the scouring process the fabric was not subjected to squeezing forces by the rollers other than that required to cause the fabric to circulate around the machine. At the end of this step the used liquor was passed to drain as the fabric was rinsed using hot water. During the rinsings the fabric was subjected to squeezing forces between the rollers.

The fabric was then transferred to a hydroextractor in which, by centrifugal action, the water and soap in the fabric was largely extracted.

The now scoured fabric was then transferred to a milling machine and was wetted out with a soap solution and subjected to mechanical working by passing it through a milling tunnel and applying pressure by virtue of the shape of the tunnel (which reduces in cross-sectional dimensions along is length from entry to exit ends). The mechanical forces to which the fabric was subjected served to create heat and the end result of milling (or fulling) caused the fabric to shrink (and thus consolidate) both warp and weft directions in a controlled manner depending upon the amount of mechanical working and the length of time that the fabric remained in the milling machine.

The milled fabric was then returned to the scouring machine and scoured using hot water only thereby to remove the soap used as a lubricant during the milling process. Finally the fabric was transferred to the hydro extractor for removal of the final rinse water.

It will be appreciated from the steps outlined above that the process of scouring and milling (or milling only) required the use of three different machines thus high capital outlay and that appreciable quantities of non-reusable materials such as soda ash and soap were required. This process also called for the repeated manual handling of the fabric.

It will be understood the cost of scouring and milling is appreciably affected by the fact that fresh quantities of soda ash and soap are required for every batch of fabric treated and by the fact that liquors containing these materials have to be disposed of.

More recently the applicants have devised a combined scouring and milling machine (described in co-pending Application No.

7912812 for the grant of Letters Patent) in which the process steps set out above can all be carried out (with the exception of centrifuging the fabric) and thus capital costs can be reduced, as in fact can the amount of manual labour involved. The cost of the treatment materials and of the disposal of stitch materials has not, however, been reduced and thus it is the primary object of the present invention to provide an improved process for the scouring and milling of fabric during which savings can be achieved in the quantities of materials, and in particular soap and soda ash.

Thus according to the present invention the method of scouring and milling a woven fabric in a combined scouring and milling machine includes the steps of milling the fabric by wetting out with a water/soda ash liquor, recovering the liquor for re-use and continuing the milling operation until completed, scouring the milled fabric initially by the application thereto of a water/soda ash liquor, rinsing the fabric with water, washing the fabric with a liquor containing soap and soda ash and finally rinsing the fabric with water to remove residual soap and soda ash.

The invention will now be described further, by way of example only with reference to one practical form thereof.

To carry out the method of scouring and milling there is provided a combined scouring and milling machine of the kind disclosed in our co-pending application No. 791281 2 for the grant of Letters Patent. Basically this machine comprises a housing within which, in the upper region thereof there is provided a pair of squeeze rollers to apply traction to the fabric. The proximity of the squeeze rollers to each other can be adjusted from a position in which they apply just sufficient pressure to the fabric to pass it between them to a position in which a substantial squeezing pressure can be applied. Upstream of these rollers is a liquor spray nozzle connected to a liquor supply pump and supply tank.Downstream of the rollers is provided a milling tunnel the dimensions of part at least of which are adjustable and which decreases in cross-sectional area from its inlet adjacent to the rollers to its outiet remote from the rollers. Below the rollers and milling tunnel and above the above of the housing is located a liquor recovery trough from which, by means of outlet pipes and valves, liquor can be directed as desired either back to a liquor supply tank or into the lower region of the housing and from there either to the supply tank or to drain. Water supply spray nozzles are also provided upstream of the rollers.

Further detail of the machine construction will not be set out since it is not thought necessary for the understanding of the present invention.

To carry out the method of scouring and milling the supply tank for the liquor spray nozzle is initially filled with a water/soda ash liquor. The machine is loaded with fabric and with the drive rollers set just to cause the fabric to be fed to the milling tunnel and with the milling tunnel adjusted to apply milling pressure the machine is started.

As the fabric is being fed to the milling tunnel the liquor is sprayed onto it completely to wet it out.

As the fabric passes between the rollers and down the milling tunnel the liquor is pressed out of the fabric and flows into the recovery trough from which it is returned to the supply tank either directiy or via the lower region of the housing.

When the fabric is fully wetted out the fabric is squeezed to remove and recover as much of the liquor as possible and this liquor is all returned to the supply tank for re-use. The milling process is now completed by circulating the fabric around the machine and down the milling tunnel. At the completion of the milling operation the fabric still contains substantially all of the materiai and added oils. The milled fabric is now scoured. For the purpose of scouring, the movable parts of the milling tunnel are positioned such that the tunnel dimensions are at their maximum size.

The recovered water/soda ash liquor is now sprayed onto the fabric as it is circulated around the machine and excess liquor is allowed to flow from the recovery trough into the lower region of the housing to form a reservoir through which the fabric is repeatedly passed until the soda ash has removed substantially all of the oils from the fabric. The fabric is now rinsed by spraying it with clean hot water and at the same time draining the oily water/soda ash liquor from the reservoir.

During this cycle the rollers are set to apply substantial squeeze pressure to the fabric. This used liquor and hot water is discharged to drain.

The supply tank is now filled with a soap/soda ash/water liquor and with the rollers set to draw the fabric around the machine without substantial squeeze pressure the fabric is sprayed with the liquor from the supply tank to wash the fabric and remove any residual oils. This liquor can be fed from the recovery trough either to drain or into the lower part of the housing to form a reservoir through which the fabric is passed during the washing cycle.

Finally the fabric is again rinsed with clean hot water to remove the soap therefrom and during this cycle the rollers are set to squeeze the fabric.

Dirty liquor from the lower region of the housing in the case in which the soap/soda ash/water liquor has been used to form a reservoir, is led to drain together with the rinsing water. When the fabric has been rinsed completely the water supply is cut off and the fabric is squeezed by the rollers to remove as much water as possible prior to removing the milled/scoured fabric from the machine.

It will be appreciated that in the process described above the fabric is only handled twice by the machine operative, that is to load and unload the machine. By recovering the water/soda ash liquor used simply to wet out the fabric for the purpose of milling and then re-using it at the commencement of the scouring operation the operator saves the cost of one quantity of soda ash.

In addition to the advantages just mentioned the process also has the advantage that a smaller quantity of effluent is created and thus effluent removal charges can also be reduced.

The invention is not restricted to the details set out above. For example, further savings in soda ash cost can be achieved during the so called "Greasy milling" process if the machine is provided with a second supply tank. In this case one supply tank is used to contain soda ash/water liquor to be used only for the purpose of initial wetting out of the fabric prior to milling. Thus this liquor, topped up from time to time can be used many times before it becomes so contaminated with oils as to be unusable even for the simple wetting out process. The other supply tank would be used initially to contain soda ash/water liquor to be used once at the initial part of the scouring operation. This tank would, after this part of the scouring process be re-charged with the soap/soda ash/water liquor used for the washing of the fabric after it had been subjected to the first hot water rinse.

Claims (12)

1. A method of scouring and milling a woven fabric in a combined scouring and milling machine including the steps of milling the fabric by wetting out with a water/soda ash liquor, recovering the liquor for re-use and continuing the milling operation until completed, scouring the milled fabric initially by the application thereto of a water/soda ash liquor, rinsing the fabric with water, washing the fabric with a liquor containing soap and soda ash and finally rinsing the fabric with water to remove residual soap and soda ash.

2. A method of scouring and milling a woven fabric in a combined scouring and milling machine as claimed in Claim 1, in which wetting out is effected by spraying the fabric.

3. A method of scouring and milling a woven fabric in a combined scouring and milling machine as claimed in Claim 1 or 2, in which the water/soda ash liquor is recovered after wetting out by squeezing the fabric.

4. A method of scouring and milling a woven fabric in a combined scouring and milling machine as claimed in Claims 1, 2 or 3, in which the milled fabric is scoured by spraying recovered water/soda ash liquor onto the fabric whilst circulating it round the machine allowing excess liquor therefrom to form a reservoir and repeatedly passing the fabric through this reservoir until the soda ash has removed substantially all the oil from the fabric.

5. A method of scouring and milling a woven fabric in a combined scouring and milling machine as claimed in any preceding claim, in which the fabric is rinsed by spraying it with clean hot water.

6. A method of scouring and milling a woven fabric in a combined scouring and milling machine as claimed in Claim 5, in which, during the rinsing cycle, substantial squeeze pressure is applied to the fabric and used liquor and hot water is discharged to drain.

7. A method of scouring and milling a woven fabric in a combined scouring and milling machine as claimed in any preceding claim, in which washing is effected by spraying the fabric with the washing liquor.

8. A method of scouring and milling a woven fabric in a combined scouring and milling machine as claimed in Claim 7, in which during washing the fabric is drawn through the machine without being subjected to substantial squeeze pressure.

9. A method of scouring and milling a woven fabric in a combined scouring and milling machine as claimed in Claim 7 or 8, in which used washing liquor is recovered to form a reservoir through which the fabric is passed during the washing cycle or is drained away.

10. A method of scouring and milling a woven fabric in a combined scouring and milling machine as claimed in any preceding claim, in which final rinsing is effected with clean hot water, the fabric being squeezed during this cycle.

11. A method of scouring and milling a woven fabric in a combined scouring and milling machine as claimed in any preceding claim, in which two supplies of water/soda ash liquor are provided, one being used simply for wetting out and the other for the initial part of the scouring cycle, this second supply being recharged with soap/soda ash/water liquor for washing the fabric after the first rinse.

12. A method of scouring and milling a woven fabric in a combined scouring and milling machine substantially as hereinbefore described.