GB2126924A

GB2126924A - Foam finishing fabrics

Info

Publication number: GB2126924A
Application number: GB08300020A
Authority: GB
Inventors: Gregory J Hopkins
Original assignee: Dexter Chemical Corp
Current assignee: Dexter Chemical Corp
Priority date: 1982-09-13
Filing date: 1983-01-04
Publication date: 1984-04-04
Also published as: IT8319817A1; FR2532961A1; ES8503049A1; GB2126924B; IL67753A0; ES530216A0; IT1161622B; DE3332824A1; FR2532961B1; ES519396A0; ES8405456A1; DE3332824C2; IT8319817A0; IL67753A; GB8300020D0

Abstract

An apparatus for continuous foam finishing of fabrics includes a pressure manifold for delivery of foam under pressure to a moving fabric (12) comprising inner and outer concentrically disposed conduits (16, 24). The inner conduit (16) receives foam under pressure from both ends (18, 20) and has a slotted port (22) along the length thereof supplying foam to the outer conduit. The outer conduit (24) includes a slotted port (26) along the length thereof for delivery of foam under pressure to the fabric passing across the port. Alternatively the pressure manifold includes three concentrically disposed conduits. The outer portions of the port (26) are adjustably sealed depending on the width of the fabric by seals (32, 34), the position of which are controlled by fabric edge sensors (36, 38). <IMAGE>

Description

SPECIFICATION Foam finishing apparatus This invention relates to an apparatus for the continuous foam finishing of a moving fabric.

More specifically, it relates to an apparatus for supplying foam to moving fabric under pressure in an even manner so that consistent, high quality foam-finished fabrics are obtained. Even more specifically, the invention relates to a novel pressure manifold for delivery of foam to a moving fabric and to means for adjustably sealing the outer portions of the manifold depending on the width of the fabric being finished.

In recent years and in particular since the advent of higher energy costs, much research effort has been devoted to the development of fabric-finishing processes which are more energy efficient than conventional finishing processes. In the latter processes, the fabric is immersed in a bath containing the finishing agent and it is thereafter dried and further processed. In conventional processes immersion of the fabric causes absorption of the finishing agent (dyestuff or sizing agent or the like) in the fiber which may result in swelling and distortion and consequent weakening of those fibers. The conventional processes also have the substantial cost disadvantage of requiring substantial energy to remove the solution or dispersion liquid in which the finishing agent is contained.

Foam finishing processes such as are described in U.S. Patent No. 3,762,860 have received substantial attention and much research effort has been expended in developing such processes as alternatives to the conventional fabric-finishing processes wherein solutions or dispersions are required. The obvious advantage is that substantially less liquid per unit amount of finishing agent need be applied to and then removed from the fabric.

It is known in foam-finishing processes to apply a foam containing the finishing agent to a moving fabric by means of a horizontal pad operation. The foam is supplied via a suitable applicator onto the surface of a moving fabric so as to create a bank of foam on that fabric. In one known technique the foam is supplied just upstream of a doctor blade, the latter causing the foam to accumulate on the fabric in the desired bank.

In another conventional technique the foam is supplied via a suitable applicator to the area between a rotating fabric roller and a closely adjacent rubber nip roller. A bank of foam is formed in the area defined by the fabric and nip rollers, respectively.

There are certain inherent disadvantages in the known methods for applying finishing agents from foams applied to moving fabrics. One disadvantage is that it is difficult to closely control the exact amount of finishing agent which is applied to the fabric because it is difficult to achieve and maintain a steadystate operation. The controls available to the foam-finishing operator are the height of the bank of foam which is applied and maintained, the density of the foam (or its inverse, known as the blow ratio), the amount of liquid containing finishing agent which is supplied to the foaming apparatus per unit time and the stability of the foam which is created, the latter being essentially a function of the choice and amount of surfactant which is used.The actual rate of absorption of the foam onto the moving fabric is determined by the wetting action of the foam as it contacts the fabric being finished.

Although manipulation of these controls results in satisfactory operation of some processes, the inherent problems in controlling and metering the amount of finishing agent which is applied to the moving fabric often manifests itself in finished goods having varying amounts of finishing agent applied across its surface. This results in offspecification goods. In foam dyeing processes in particular, non-uniformity is visually unacceptable.

The non-uniformity may be in part a function of currents set up in the foam bank itself by the moving fabric or by the fabric and nip rollers and may be in further part due to non-uniform delivery of foam across the width of the fabric.

Still another problem of applying foam from a bank is that there is essentially no control over the pressure of the foam application. It is frequently desirable to vary the pressure of the application depending upon the thickness of the fabric to be finished, the wetting characteristic of the fibers, whether or not the fabric is to be finished on both sides and other considerations. Conventional foam finishing techniques do not provide the desired flexibility or control.

It is therefore a primary object of this invention to provide apparatus for supplying foam to a moving fabric which avoids the problems of the prior art techniques and which delivers foam in a uniform amount per unit time to a moving fabric.

It is a further related object of this invention to provide a foam delivery system which includes a manifold which achieves the uniform distribution of foam across the width and length of a moving fabric.

It is a further and related object of this invention to provide a foam delivery system including a manifold which controls the pressure of the foam being applied to a moving fabric so that the rate of supply of the foam can be closely controlled.

It is a further object of this invention to provide a continuous and automatic system for applying a uniform amount of foam to a moving fabric per unit time so that the incidence of off-specification finished goods will be reduced.

It is a further object to control the pressure of the foam application so that fabrics of varying thickness and characteristics can be dyed exactly as desired.

It is yet a further and related object of this invention to provide a foam delivery system which takes the guesswork and difficulty out of methods presently in use for foam-finishing fabrics.

It is still a further object of this invention to reduce to an absolute bare minimum the liquid pick-up of the fabric (pounds of water or solvent per pound of fabric) in the foam finishing apparatus in order to limit further processing costs.

These and other objects of the invention are achieved in a foam delivery system which broadly includes a pressure manifold for supplying foam under pressure to a continuously moving fabric and a means for a continuously moving fabric across that manifold. The pressure manifold includes at least two conduits, an inner conduit to which foam is supplied under pressure having an effluent port along its length, and an outer conduit, larger than the inner conduit and surrounding the inner conduit, having a slotted port along its length for delivery of foam under pressure to the moving fabric. The means for moving the fabric across the pressure manifold may be any conventional system including fabric rolls and the like.

The invention is described in detail in connection with the drawings.

In the drawings: Fig. 1 is a perspective view of the foam delivery apparatus of the invention; Fig. 2 is a sectional view of the foam manifold of the invention taken along lines 2-2 of Fig. 1; Fig. 3 is a sectional view of the manifold of the invention taken along lines 3-3 of Fig. 2; and Fig. 4 is a sectional view of the manifold taken along lines 4-4 of Fig. 2.

Referring to the drawings, reference numeral 10 refers generally to a foam-finishing apparatus according to the invention including a moving band of fabric 12 which passes across a pressure manifold 14. Conventional means such as rollers, not shown, are provided to move fabric 12.

Pressure manifold 14 includes an inner conduit 1 6 to which foam containing a finishing agent is supplied. While foam may be supplied at either end, desirably it is supplied by means of positive displacement pumps from both end 18 and end 20 of inner conduit 1 6. Conduit 1 6 may be of any suitable material but preferably is polyvinyl chloride or stainless steel. Inner conduit 16 is provided with an effluent port along the length thereof which may be series of spaced holes or, preferably, as is shown in Fig. 1, is a continuous slot 22 extending along the length of conduit 1 6.

Manifold 14 further includes an outer conduit 24 which surrounds and desirably is concentrically disposed with respect to inner conduit16. Outer conduit 24 is provided with a slotted effluent port 26 which extends along the length of conduit 24 and through which foam is delivered under pressure to moving fabric 1 2 which passes across slotted port 26.

Inner conduits 1 6 and 24 are sealed at their outer ends by means of fixed, annular, end seals 28 and 30. Inwardly of fixed seals 28 and 30 are adjustable seals 32 and 34 which are sleeves concentrically disposed about outer conduit 24 and movable along the axis of conduit 24.

Adjustable seals 32 and 34 prevent flow of foam out of effluent slot 26 in those portions which are sealed off.

Foam delivery system 10 further includes palm sensors 36 and 38 which sense the position of the outer edges 1 2a and 1 2b, the selvages, of fabric 1 2 as it passes towards the foam-finishing manifold 14. Palm sensors 36 and 38, as are well understood in the art, are provided with means for developing a signal which is a function of the position of the edge of the fabric, the signal being relayed to pneumatic cylinders 40 and 42 which are movable in response to such signals to adjust the position of movable seals 32 and 34 by the action of connecting arms 44 and 46.

In a preferred embodiment of the invention the inner conduit 1 6 may be a T inch pipe having an effluent port 22 which is a slot 1/64th inch wide extending along the length of conduit 1 6. The outer conduit 24 may be a 26 inch pipe having an effluent port 26 which is a slot T inch wide along the length thereof. Conduit 24 may be, but need not necessarily be, concentrically disposed with respect to inner conduit 1 6.

In foam finishing processes wherein wide fabrics are treated, or where high pressures are required for driving the foam into a thick fabric in order to finish both sides thereof, it is preferable to use a manifold containing three conduits positioned one within the other. Theoretically, four or more conduits disposed within one another can be used although no further advantage is obtained.

Where three conduits are employed. the inner conduit communicates at both ends with a source of foam under pressure and has an effluent port, desirably a slot, along its length. A second conduit, larger than the inner conduit is desirably concentrically disposed with respect to the inner conduit and it too has a slotted effluent port along the length thereof. The third conduit, desirably concentrically disposed with respect to the other two has a slotted port along its length for delivery of foam under pressure to a moving fabric.

It has been found that the three-conduit manifold uniformly delivers foam along the width of the fabric because the inner pipes act as restriction orifices supplying foam at high and uniform pressure all along the effluent slot of the outer conduit. Conversely, it has been found that where one slotted pipe is employed there is nonuniform flow of foam from a slotted effluent such that less foam is supplied to the center areas of the conduit as contrasted with the outer areas.

This results in non-uniform application of finishing agent to the fabric and is obviously unsatisfactory.

It has been found that the foam delivery system of the invention provides great flexibility in applying foam under closely controlled pressure to a variety of fabrics of different characteristics and thicknesses. By using either two- or three-conduit manifolds and by varying the widths of the effluent ports in the inner and outer conduits, it is possible to achieve a measure of positive control over the supply of foam to the fabric that has heretofor not been obtainable. In addition, it has been found that the water pick-up can be as low as 10% or less whereas in prior art foam bank techniques the water pick-up is 15% or higher. This results in very substantial savings in further processing and in the energy required to remove the water or other solvent from the finished fabric. This substantial reduction in water pick-up can be attributed to the smaller contact area between the foam and the fabric in the invention as contrasted with the area of contact in the foambank operations of the prior art.

It has also been found that the foam delivered with -the manifold and system of the invention is uniformly distributed across both the length and width of the fabric being finished whereas in prior art devices there are non-uniformities due to variations in the pressure of the foam being applied to the fabric.

Claims

1. A pressure manifold for delivery of foam to a moving fabric in a foam finishing apparatus including (a) an inner conduit communicating at at least one end with a source of foam under pressure and having effluent port means along the length thereof; and (b) an outer conduit larger than said inner conduit and surrounding said inner conduit, said outer conduit having a slotted port along the length thereof for delivery of foam under pressure to a moving fabric passing across said slotted port.

2. A pressure manifold as recited in claim 1 wherein said inner conduit communicates at both ends with a source of foam under pressure.

3. A pressure manifold as recited in claim 1 wherein said effluent port means in said inner conduit is a slot extending along the length of said inner conduit.

4. A pressure manifold as recited in claim 1 wherein the inner and outer conduits are concentrically disposed with respect to one another.

5. A pressure manifold for delivery of foam to a moving fabric in a foam finishing apparatus including (a) an inner conduit communicating at both ends with a source of foam under pressure and having a slotted effluent port along the length thereof; and (b) an outer conduit larger than said inner conduit and surrounding and being concentrically disposed with respect to said inner conduit, said outer conduit having a slotted port extending along the length thereof for delivery of foam under pressure to a moving fabric passing across said slotted port.

6. A pressure manifold for delivery of foam to a moving fabric in a foam finishing apparatus including (a) an inner conduit communicating at at least one end with a source of foam under pressure and having effluent port means disposed along the length thereof; (b) a second conduit larger than said inner conduit and surrounding said inner conduit, said second conduit having effluent port means along the length thereof; and (c) a third conduit, larger than said second conduit and surrounding said second conduit, said third conduit having a slotted port along the length thereof for delivery of foam under pressure to a moving fabric across said slotted port.

7. A pressure manifold as recited in claim 6 wherein said inner conduit communicates at both ends with a source of foam under pressure.

8. A pressure manifold as recited in claim 6 wherein said effluent port means in said first and second conduits are slots extending along the length thereof.

9. A pressure manifold as recited in claim 6 wherein said first, second and third conduits are concentrically disposed with respect to one another.

10. A foam delivery system for supplying foam under pressure to a moving fabric in a foam finishing apparatus, including (a) means for supplying foam under pressure to a manifold, said manifold including (1) an inner conduit communicating at at least one end with a source of foam under pressure and having effluent port means disposed along the length thereof, and (2) an outer conduit larger than said inner conduit and surrounding said inner conduit, said outer conduit having a slotted port along the length thereof for delivery of foam under pressure to a moving fabric passing across said slotted port, and (b) means for continuously moving a fabric across the said slotted port in the outer conduit of said manifold.

11. A foam delivery system as recited in claim 10 including means for adjustably sealing portions of the slotted delivery port in said outer conduit.

12. A foam delivery system as recited in claim 10 including means for adjustably sealing the outer edges of the said slotted port in the outer conduit, said adjustable sealing means comprising sleeve members disposed about the outer edges of said outer conduit and being movable along the axis of said outer conduit to adjust the length of said slotted port.

13. A foam delivery system as recited in claim 12 wherein the said adjustable sleeve members are movable to a plurality of positions corresponding to the positions of the outer edges of the fabrics moving across the said slotted port.

1 4. A foam del;very system as recited in claim 1 3 wherein means are provided to sense the positions of the outer edges of the fabric being continuously furnished for foam finishing, said means providing a signal which is a function of the said position of the edges of said fabric, and further including means to adjust the position of said manifold sealing means in response to said signal so that said sealing means are in contact with the selvage of said fabric as it moves across the said slotted port.

1 5. A foam delivery system for supplying foam under pressure to a moving fabric in a foam finishing apparatus including (1) means for supplying foam under pressure to a pressure manifold, said pressure manifold including (a) an inner conduit communicating at both ends with a source of foam under pressure and having a slotted effluent port along the length of said conduit for passage of said foam; and (b) an outer conduit larger than said inner conduit and surrounding and being concentrically disposed with respect to said inner conduit, said outer conduit having a slotted port extending along the length thereof for delivery of foam under pressure to a moving fabric passing across said slotted port, (2) means for continuously moving a fabric across the said slotted port in the outer conduit of said manifold; (3) means for adjustably sealing the outer portions of the said slotted port in the outer conduit; (4) means for sensing the position of the edges of the fabric furnished to said slotted port including means for developing a signal which is a function of the position of the edges of said fabric; and (5) means responsive to said signal for adjusting the said sealing means so that it is in close contact with the selvage of the said fabric.

1 6. A foam delivery system for supplying foam under pressure to a moving fabric in a foam finishing apparatus including (1) means for supplying foam under pressure to a pressure manifold, said pressure manifold including (a) an inner conduit communicating at at least one end with a source of foam under pressure and having effluent port means along the length thereof for passage of said foam; (b) a second conduit iarger than said inner conduit and surrounding said inner conduit, said outer conduit having effluent port means along the length thereof for passage of said foam; and (c) a third conduit, larger than said second conduit and surrounding said second conduit, said third conduit having a slotted port along the length thereof for delivery of foam under pressure to a fabric moving across said slotted port, (2) means for continuously moving a fabric across the said slotted port in the third conduit of said manifold; (3) means for adjustably sealing the outer portions of the said slotted port in the outer conduit; (4) means for sensing the positions of the edges of the fabric furnished to said slotted port including means for developing a signal which is a function of the position of the edges of said fabric; and (5) means responsive to said signal for continuously adjusting the said sealing means so that it is in close contact with the selvage of the said fabric.

1 7. A pressure manifold for delivery of foam to a moving fabric, comprising an inner conduit having effluent port means along the length thereof and adapted to communicate with a source of foam under pressure; and an outer conduit larger than said inner conduit and surrounding said inner conduit, said outer conduit having a slotted port along the length thereof for delivery of foam under pressure to a moving fabric passing across said slotted port.

18. A pressure manifold for delivery of foam to a moving fabric in a foam finishing apparatus, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

19. A foam delivery system for supplying foam under pressure to a moving fabric in a foam finishing apparatus, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.