APPARATUS FOR TREATING FABRICS WITH FOAM

Abstract: Foam generating apparatus comprises a liquid reservoir (1) and a pump (3) for re-circulating liquid from said reservoir through a closed circuit back to said reservoir, said closed circuit including valve means (5) responsive to at least the linear speed of a fabric to be treated with foam and serving to divert liquid from the closed circuit to a foam generator (8) wherein it is admixed with air to form a foam for application to the fabric.

Description: Imorbvements in and relating to fabric finishing This invention relates to the treatment of textile materials such as fabrics with solutions or dispersions of dyestuffs, colourinq materials, textile finishinq auxiliaries such as resins, and the like. In the interests of simplicity the term "textile auxiliary" will be used to denote all such liquid treatments. It is know that- the application of textile auxiliaries can be nore econonically and/or efficiently carried out by applying them as a foam. However, the apparatus for this purpose has hitherto been both complicated and expensive. Accordinq to the present invention we provide apparatus comprising a liquid reservoir for textile auxiliary solution or dispersion and a pump for re-circulating liquid fron said reservoir through a closed circuit back to said reservoir, said closed circuit including valve means responsive to at least the linear speed of a fabric to be treated "ith foam and serving to divert liquid fron the closed circuit to a foam generator wherein it is admixed with air to form a foam for application to the fabric. Preferably, the apparatus includes a control system for the valve means, the control systen comprising an actuator for the valve means and an associated control module for the actuator responsive at least to fabric speed. Preferably, the control nodule is also responsive to input signals related to fabric width and/or fabric weight. These latter signals may be provided as pre-set, constant inputs, in which case the fabric Speed may be used to effect overall, or major control of the setting of the valve means. It will be appreciated that the valve means must divert progressively more liquid to the foam generator as the fabric speed proqressively increases, and vice-versa. The foam generator itself is preferably a column supplied at one end with liquid and air under pressure and containing a medium such as glass beads to form foam from the liquid/air mixture. According to a further aspect of the invention, the column just mentioned is preferably arranqed to supply the foam to textile finishing apparatus through a tailpipe itself containing a foam qeneratinq- medium such as a knitted wire-mesh. The length of this tailpipe is preferably adjustable, for example, hy making it from a plurality of discrete sections which are connectable in series. This is particularly advantageous because it enables the liquid dwell time in foam generation to be tailored to accommodate different throughputs, as well as to accommodate different kinds of auxiliary solution or dispersion. This is especially relevant to the surfactant used in making up the auxiliary solution or dispersion because surfactant properties vary quite widely. In order that the invention be better understood, a preferred embodiment of it will now be described by way of example with reference to the accompanyinq drawing which is a schematic illustration of one apparatus in accordance with the invention. In the drawing, a reservoir 1 contains a solution or dispersion of a textile auxiliary, 2, together with a surfactant to render it more readily foamable. Other materials, such as softening agents, may also be present; in the case of a resin, a thermally activated catalyst will usually be also included. A pump 3 is provided to re-circulate the solution 2 through a closed circuit 4 including a proportionating or diverter valve 5. The latter valve has an output connection 6 leading to a foam generator comprising a foaming column 8 supplied with air and liquid together at one end. The column is packed with glass beads (not shown) and its other end communicates with a tailpipe 10 which serves to connect the foam generator to textile fabric treatment apparatus 18. The tailpipe 10 is packed with knitted wire mesh, 11. The valve 5 is operated by a control unit comprising an actuator 13 and a control module 14. Details of the latter are not qiven because there are many ways of implementing the desired control functions. The module is arranged to respond to three control inputs; one of these (15) is a fabric/speed signal from the fabric treatment apparatus mentioned above. The other two inputs (16 and 17) are supplied with pre-set, fixed input signals corresponding to fabric width and fabric weight. These are based on calibration of the system, for given fabrics and various values of fabric auxiliary pick-up desired. Once set up, the fabric speed signal effects overall, or major control of the rate of foam generation, through operation of the control unit. It will be appreciated that the fabric treatment apparatus 18 may be a resin finishing machine, a dyeing machine or a fabric printing machine. In the latter case, separate apparatus may be provided to foam each colouring liquid applied and a common control module 14 may be tised to effect control of each such apparatus.

Claims: CLAIMS:- 1. Foam generating apparatus characterised in that it comprises a liquid reservoir and a pump for re-circulating liquid from said reservoir through a closed circuit back to said reservoir, said closed circuit including valve means responsive to at least the linear speed of a fabric to be treated with foam and serving to divert liquid from the closed circuit to a foam generator wherein it is admixed with air to form a foam for application to the fabric. 2. Apparatus according to claim 1 further characterized by an actuator for the valve means and an associated control module for the actuator responsive at least to fabric speed. 3. Apparatus according to claim 2 charactrised in that the control module is also responsive to input signals related to fabric width and/or fabric weight. 4. Apparatus according to claim 3 characterised in that the input signals are preset, constant inputs and the fabric speed effects overall or major control of the setting of the valve means. 5. Apparatus according to anyereceding claim characterised in that the foam generator is a column supplied at one end with liquid and air under pressure and containing a medium such as glass beads to form a foam from the- liquid and air mixture in passage through said medium. 6. Apparatus according to any preceding claim characterised in that the foam is supplied in textile finishing or treatmnet apparatus through a pipe containing a foam generating medium. 7. Apparatus according to claim 6 charadterised in that the pipe is constructed as a plurality of d'screte sections connectable in series.

Inventors: OGDEN, DENNIS HENRY
Applicants: BRITISH INDUSTRIAL PLASTICS LIMITED
Application year: 1982
Main classification: D06B19
IPC codes: D06B19