EP0097183B1 - Device for transforming into foam a treatment liquid - Google Patents

Description

The invention relates to a device for foaming a treatment liquor in a mixing chamber used for foaming, with a static means adjoining the chamber exit for mixing and dividing the pipeline having the foamed liquor.

With the aid of the device according to the invention, chemicals and / or dyes should be foamed in sufficient quantity that a textile web or the like is to be coated with the foam continuously in a uniform application quantity over the full width of the web and in the direction of travel. In particular, the fineness or bubble size of the foam should be adjustable independently of the amount of foam produced per unit of time. With devices used hitherto, this device can only be fulfilled with great effort or only incompletely.

A device of the type mentioned is described in US Pat. No. 3,388,868. This document discloses a device for foaming a treatment liquor in a rammer used for foaming, with static means for fine foaming adjoining the rammer outlet. In the known, sieves are used as a means of fine foaming, which are used in a pipeline.

In a device for foaming a treatment liquor known from DE-A-25 23 062, the mixing chamber filled with glass balls is supplied with liquid treatment liquor and compressed air from opposite sides. In many cases, the fineness of the foam to be achieved in the mixing chamber is not sufficient to fulfill the treatment task. In practice, therefore, the liquor foamed in the mixing chamber is fed to a device for mechanical fine foaming. In a device of this type previously used, a shaft with radially projecting rods is rotatably mounted in a hollow cylinder which has rods directed radially towards the shaft on the inner surface. Such a device must be manufactured with great precision and stability if it is to deliver the desired success without problems.

The object of the invention is to improve a device for producing foam that operates without moving parts so that the fineness of the foam can be specified in any way. The solution according to the invention for the device mentioned at the outset with a static means for mixing and dividing the foamed liquor having pipeline connected to the outlet of a mixing chamber is that the length of the pipeline, in particular by connecting or shutting off shunt loops, for adjusting the fineness of the Foam is changeable.

According to the invention, the fineness of the foam to be produced can be predetermined by lengthening or shortening the length of the packing in the pipeline measured in the flow direction of the foam and of course the pipeline itself accordingly. This means that the foam fineness can be specified solely by the length of the pipeline without changing any other parameters - at least in a wide mixing range of the starting solution. The achievable fineness can also be preset by selecting the ratio of the treatment solution supplied to the mixing chamber and the pressure of the compressed air, because this specifies the fineness of the foam bubbles supplied to the static foam-dividing agents in the pipeline and thus the initial size of the foam bubbles.

As a means for mixing and dividing the bubbles of the foamed liquor, a packing contained in the pipeline can be provided from a multiplicity of small sections of sharp-edged small particles which are small compared to the dimensions of the pipeline, such as sections or broken tubes, in particular made of glass. Preferably, the pipeline provided for fine foaming should contain a filling made of glass tube sections, known per se from devices for fractional distillation - so-called Raschig rings.

If the liquor, which is more or less foamed in the mixing chamber, meets a pack of sharp-edged small particles permeable in the longitudinal direction of the pipeline on any intertwined and intersecting paths, the foam bubbles already present are repeatedly divided at the edges and with each other and with the mixture containing air mixed. During this process of foam separation, the pressure is increased. This in turn turns the original spherical foam into so-called polyhedron foam. It is of course assumed that the starting solution contains a foam stabilizer.

In the device according to the invention it is also advantageous to foam the liquor as well as possible in the mixing chamber. According to a further invention, this is achieved in a device in which a liquid inlet of the rammer is fed into a liquor liquor and foamed with compressed gas fed in by the fact that the pressurized gas supply line extends into the region of the liquor inlet of the chamber and that the outlet of the pressurized gas supply line essentially has a spray head has the direction of flow of the fleet to be supplied finely divided gas outlets.

By juxtaposing compressed gas, in particular compressed air, and flots at the liquor inlet of the mixing chamber, a kind of atomization with the formation of small bubbles is achieved from the outset. The finer that on the Brisk directed gas jets are, the finer the foam bubbles are. It is therefore favorable to design the spray head from fine-pored material, in particular from a sintered body with continuous pores, for example according to the type of silencer.

Finally, the mixing chamber itself, like the downstream pipeline, can also be filled with static means for mixing and dividing the liquor foamed on the spray head. A relatively well finely foamed treatment liquor then already enters the pipeline provided for fine foaming with a variable length according to the invention, and the partial action of the static foaming agent in the pipeline can foam increasingly finely starting from this fine foam.

If large amounts of foam with very fine bubbles are to be generated with the device according to the invention, a correspondingly long pipeline containing static foam-breaking agents is required. If the fineness of the foam produced is to be increased without changing the amount of treatment liquor and compressed air, the pipeline is shortened according to the invention. The pipeline is therefore preferably equipped with a by-pass loop to be switched on or off via a tap. When the tap is open, the path effectively to be covered in the pipeline is shortened by the respective shunt in such a way that a foam of less fineness is produced. When the tap is closed, on the other hand, the foam must pass through the entire path of the pipeline in the bypass loop, so that a correspondingly finely divided foam is formed.

• Fig. 1 eine Verschäum-Vorrichtung im Querschnitt; und
• Fig. 2 eine Verschäum-Vorrichtung mit Nebenschluß.

Further details of the invention are explained on the basis of the schematic illustration in the drawing. Show it:

• 1 shows a foaming device in cross section. and
• Fig. 2 shows a foaming device with a shunt.

1 and 2, a mixing chamber with liquor inlet 2, compressed gas inlet 3 and mixture or foam outlet 4 is shown schematically. According to the invention, a pipe 6 filled with static means S for mixing and dividing the foamed liquor is connected to the latter. In the mixing chamber 1 can be foamed in the arrow direction 7 via a pump, not shown, to the fleet inlet 2, to be foamed, with pressurized gas, in particular compressed air, fed separately via line 3 in the direction of arrow 8. A relatively good foaming is already obtained at this point if the compressed gas supply line 3 extends into the liquor inlet region 9 of the chamber and if the outlet of the compressed gas supply line 3 has a spray head 10 with the flow direction 7 of the liquor to be supplied directed essentially opposite to the flow direction 7, has finely divided gas jets.

As a means for mixing and dividing the bubbles of the foamed liquor that have already been produced in the mixing chamber 1, according to the invention a pack of a plurality of small sections of tubes or fragments of tubes, in particular of glass, which are small compared to the dimensions of the pipeline, is provided. These static means 5 for fine foaming should be designed so that they let the foam pass easily in the longitudinal direction 11 of the pipeline 6 but often pass back and forth on the way and cross and constantly break up on sharp edges. In order to prevent the static means for finely distributing the foam from the pipeline 8 from falling into the mixing chamber 1, the associated foam outlet 4 of the mixing chamber 1 is preferably closed with a sieve 12. In principle, however, the mixing chamber 1 can also be partially or completely filled with the static means 5 or similar particles for finely distributing the foam generated in the liquor inlet area 9.

Since the fineness of the foam to be produced with the device according to the invention depends solely on the length of the pipeline 6 with otherwise unchanged parameters, it may be advantageous to change the length of the pipeline 8 alone in order to adapt the fineness of the foam to the respective requirements. To adjust the length of the pipeline accordingly, it may therefore be advantageous if the pipeline contains one or more shunts 13 according to FIG. 2 with, for example, a 2-way valve 14. With the help of an appropriate cascade circuit, any desired fineness of the foam can be achieved without significant effort.

Claims (5)

1.) Device for foaming a treatment bath in a mixing chamber (1) serving for foam formation, with a conduit (6) adjoining the chamber exit (4) and comprising static means (5) for intermixing and distribution of the foamed-up bath, characterised in that the length of the conduit (6) is variable for the adjustment of the fineness of the foam, especially by the connection or shutting-off of parallel-connected loops (13).

2.) Device according to Claim 1, characterised in that for the intermixing and distribution of the bubbles of the foamed-up bath the conduit is filled with a plurality of sections of small tubes which are small compared with the dimensions of the conduit, fragments of pipes or the like, especially of glass.

3.) Device according to Claim 1 or 2,in which liquid bath can be fed to a bath inlet (2) of the chamber and can be foamed up with compressed gas supplied therefrom through a conduit (3), characterised in that the compressed gas conduit (3) reaches into the bath inlet region (9) of the chamber (1) and in that the outlet of the compressed gas conduit (3) possesses a spray head (10) with finely divided gas outlets directed substantially oppositely to the direction (7) of flow of the bath to be supplied.

1. Dispositif pour transformer en mousse un bain de traitement dans une chambre de melange (1) servant a la formation de mousse, comprenant une conduite tubulaire (6) se raccordant a la sortie de chambre (4) et comportant des moyens statiques (5) pour le melange intime et le fractionnement du bain qui a mousse, caractérisé en ce que, pour le reglage de la finesse de la mousse, on peut faire varier la longueur de la conduite tubulaire (6), notamment par mise en ou hors circuit de boucles de derivation (13).

2. Dispositif selon la revendication 1, caractérisé en ce que, pour le mélange intime et le fractionnement des bulles du bain transforme en mousse, la conduite tubulaire est remplie d'une multiplicite de tronqons, de petites dimensions par rapport aux dimensions de la conduite tubulaire, de tubes fins, de bris de tubes ou analogues, notamment en verre.

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