EP0633960B1 - Process for washing a textile web and corresponding broad washing machine - Google Patents

Abstract

In a broad washing machine (100) for a steam permeable textile web (1) there are a steam injector (10) on one side of the web (1) and an extractor (20) on the opposite side capable of generating an underpressure of at least 0.2 bar. The outlet aperture (10') of the injector (10) and the intake aperture (20') of the extractor (20) extend over the entire width of the web. The web (1) is taken between the injector (10) and the extractor (20). Steam is injected into the web (1) and driven through it and extracted on its other side with the released residues.

Description

The invention relates to a method for washing a textile web according to the preamble of claim 1 and a wide-width washing machine according to the preamble of claim 2.

Wide washing machines for textile webs are known in various designs. A major problem in many cases is that residues of the corresponding type remain in the interior of the web from the customary pretreatment and wet finishing stages (desizing, washing out of preparations, dyeing, printing, finishing). In the case of very heavy or dense webs in particular, the expenditure of energy and washing water in the known washing processes can become very great if sufficient removal of the residues is to be achieved.

From DE 20 59 308 A 1, a generic method and such an arrangement for rinsing out washing liquor from fabric articles are known, in which steam from a rinsing unit in a mixture with entrained water from a cross-wise from above onto the web horizontally guided between sieve belts Width of the web extending slot nozzle is inflated. At some distance below the lower sieve belt there is a collecting device with an inlet opening under the slot nozzle Arranged in which the liquid which has passed through the material web and is loaded with the washed-out residues is collected without pressure and pumped back into the rinsing unit.

Experiments have shown that the washing effects which can be achieved with such an arrangement do not significantly exceed those of conventional washing units.

The invention has for its object to achieve an improved washing effect in a generic method and such a wide washing machine.

This object is achieved in its procedural aspect by the invention reproduced in claim 1.

An essential point of the present invention is that steam is injected into the web on one side and is drawn off in the vicinity of the injection area on the other side, together with the residues remaining in the web, under the effect of a strong negative pressure. It has been shown that only the blowing up of the steam under significant overpressure with practically simultaneous suction from the other side under a vacuum of at least 0.2 bar results in a substantial increase in the washing effect. The negative pressure should therefore not only be sufficient to achieve a mere removal of the medium that has passed through the material web, but should also result in a vigorous flow through the material web, so that the residues just hit by the inflated steam are, as it were, torn out of the web in this state. As a result, more effective washing is possible in a relatively simple manner (possibly in addition to conventional washing processes). The energy expenditure remains limited, since the steam or its condensate are essentially completely drawn off and can remain in the circuit. Depending on the setting of the steam, a wet web can do the wide-washing machine with a little less, a dry web can do the wide-washing machine with just less leave slightly increased moisture so that the heat content of the web remains essentially unchanged and in any case not much heat is transported out of the process in this way.

The expression "in the neighborhood" for the mutual position of the outlet opening and the inlet opening is intended to mean that the application of the steam on one side of the web and the suction from the other side are not at a greater distance from one another in the conveying direction and at a corresponding time Distance should take place, but in one go. Even if it is not imperative that the outlet opening and the inlet opening lie exactly opposite one another, and also not that both with their boundaries bear against the web under pressure (although this is the preferred embodiment), the distances between the openings should occur or their limits in the conveying direction of the web and perpendicular to the web surface are of the order of magnitude of the openings in the conveying direction, that is to say in practice are in the order of millimeters or at most a few centimeters. This close "neighborhood" makes it possible to maintain the pressures required on the pressure side and the suction side to achieve the washing effect, without having to use excessively dimensioned pressure and suction pumps.

By applying steam, thermal and mechanical energy is supplied to the web or the residues on it. In many cases, the residues consist of organic treatment agents or auxiliaries or comprise agents which have considerable molecular sizes. The idea is that these large molecules are stimulated by the energy supply until they are broken down or split up and removed by suction in the "neighborhood" in this more mobile state before they can come together again to form larger and less mobile units.

DE 31 03 359 A1 discloses a device for uniformly applying a small amount of a treatment agent in foam form to the surface of a web of a material to be treated, in which the foam is first applied from a foam application device to a sieve belt running above the web. The sieve belt then comes together with the web, with some of the foam held in the sieve belt already passing onto the web due to the mere contact. The web and the screen belt then pass through a pair of squeeze rollers. In order to support the transition, a pair of suction nozzles can be provided downstream of the pinch roller pair on the back of the web, the effect of which can in some cases be supported by a blowing nozzle arranged above the web of the suction nozzle. DE 31 03 359 A1 is therefore concerned with the application and uniform distribution of a substance on the web, which should remain on or in the vicinity and exert its effect there and which should not be broken down or split and removed from the web should.

The cleaning-supporting effect of steam is also known per se from the usual steam cleaners, in which steam is sprayed from a nozzle onto carpets or upholstered furniture, for example. The suction in one go from the other side with a strong negative pressure is missing here.

In its apparatus aspect, the invention is given in claim 2.

It has been shown that the washing effect is further improved if the vacuum on the suction side is at least 0.5 bar (claim 3).

In claims 4 to 11, various configurations of the exit or. Entry opening reproduced.

An important feature is the adjustability of the openings according to claim 12, because an adaptation to different goods is possible. For the optimal washing effect To achieve, it is understandable that the design and arrangement of the openings must be different for loose thin goods, tightly packed solid goods, pile goods and even carpets.

The adjustability is particularly advantageous in cooperation with a control and regulating device according to claim 13, which allows the washing process to be regulated as a function of goods-specific parameters, that is to say to design it automatically.

The control and regulating device can comprise several regulators assigned to the individual components of the machine; however, the combination of the essential or all control and regulating elements in a central control and regulating unit is preferred (claim 15).

According to claim 15, this can relate in particular to the flow quantity and / or the flow pressure and what the extent of the openings in the conveying direction, ie the width the slit nozzles relates to be realized in the manner shown in claim 16.

An important influencing variable for the washing process is the conveying speed of the web, which can be included in the regulation according to claim 17.

A special control variable, which is characteristic of the washing effectiveness, is the concentration of the residues washed out of the material web in the extracted medium. This can be included in the regulation according to claim 18.

Alternatively, the concentration of the residues remaining on the material web can also be determined and the corresponding concentration value can be used for regulation (claim 19).

Depending on the residues to be washed out and the peculiarity of the web, it may be useful to add a gas in addition to the steam, e.g. Air and / or a liquid, e.g. Injecting water into the web and sucking it back together with the steam on the other side (claim 20).

• Fig. 1 bis 3 zeigen in Betracht kommende Anordnungen der Austritts- und Eintrittsöffnungen;
• Fig. 4 zeigt ein Schaltbild einer speziellen Ausführungsform einer erfindungsgemäßen Breitwaschmaschine.

Exemplary embodiments of the invention are indicated schematically in the drawing.

• 1 to 3 show possible arrangements of the outlet and inlet openings;
• Fig. 4 shows a circuit diagram of a special embodiment of a wide washing machine according to the invention.

1 to 3, a textile web 1 is indicated, which is horizontally conveyed in the spread position and has a certain permeability, so that steam inflated onto the web 1 can pass through the web 1.

In the embodiment according to FIG. 1, an injection device 10 with an outlet opening 10 ′ running across the width of the web, that is perpendicular to the plane of the drawing, is provided above the web 1. The outlet opening 10 'is delimited by a slot nozzle 40, the Expansion in the conveying direction 1 'of the web 1, ie the slot width 41 is adjustable. A possible range for the slot width 41 is approximately 1 to 2 mm.

1, a suction device 20 with an inlet opening 20 'is provided below the web 1, which is formed by a slot nozzle 50 with an adjustable slot width 51. The extent of the outlet openings in the slot nozzles 40, 50 in the width direction of the web is adaptable to the width of the web 1, so that no losses in steam or suction power occur.

In the exemplary embodiment, the slot widths 41 and 51 are the same and the slot nozzles 40, 50 lie exactly opposite one another. The exit edges of the slot nozzles 40, 50 rest against the web 1 under slight pressure from both sides.

In the injection device 10, steam is generated under an overpressure of at least 0.2 bar, better still somewhat higher, e.g. in the range of 0.5 bar on the top of the web 1 and blown into it, which is indicated by the arrow I. On the opposite, i.e. in Fig. 1 lower side the medium which has passed through the web 1, i.e. a mixture of steam, water and the residues released from the material web 1 is drawn off with a vacuum of at least 0.2 bar, better still 0.5 bar, which is symbolized by the arrow A.

In the embodiment according to FIG. 2, the slot nozzle 40 corresponds to that according to FIG. 1. The web 1 lies against the nozzle edges. The slot nozzle 50 'of the suction device 20, however, has an approximately twice the width 51' as the slot nozzle 40 and is offset with its lagging boundary by a distance 52 'in the conveying direction 1'. The distance 52 'is smaller than the width 41 of the slot nozzle 40, so that the slot nozzle 50' in the region 54 'is still partially below the slot nozzle 40, but it extends in the conveying direction 1 beyond this stretches so that in area 53, in addition to the steam remaining in the web, the condensate formed there and the residues to be removed, air is sucked through the web 1 from the outside. In the area 52 'there is no nozzle opposite the outlet opening 10', but the amount of steam which exits through the web 1 into the outside space is relatively small, since in particular in the first phase the inflated steam immediately blows up and in The web of material condenses and remains largely in the slot nozzle 50 'until it is reached.

In the exemplary embodiment according to FIG. 3, the slot nozzle 50 "of the suction device 20 is approximately three times as wide as the slot nozzle 40 of the injection device 10 and is offset relative to the latter with its trailing edge by a distance 52" in the conveying direction 1 'which is greater than the width 41 of the slot nozzle 40. There is therefore no longer any overlap of the slot nozzles 40 and 50 ".

In addition, the embodiment of Fig. 3 differs from the two previous embodiments in that the edges of the slot nozzle 41 are located slightly above the web, i.e. maintain a certain distance from the web 1 perpendicular to its surface. Part of the steam blown in the direction of arrow I will therefore flow laterally parallel to the web and partially condense on it or, insofar as it passes through the slot nozzle 50 ", from the negative pressure prevailing there in the direction of arrow A into the web 1 - and are torn through them. However, the web 1 will always rest on the edges of the slot nozzles 50, 50 ', 50 ", since it is sucked in by the negative pressure prevailing there.

However, the outlet opening 10 'and the inlet opening 20' should always remain in the vicinity of one another, which should mean that the two should not be apart from one another by more than the size of a slot nozzle width. Both the transfer amounts 54 'and 54 "as well the distance 42 should therefore be only a few millimeters or centimeters. It is therefore not intended to inject the steam in the direction of arrow I at one point and to suction in the direction of arrow A at a point, for example, one meter behind it. Rather, the steam is to be applied and injected into the web 1 and sucked off again immediately or practically immediately.

The embodiment of FIG. 4 corresponds to the embodiment of FIG. 1 with regard to the design and arrangement of outlet opening 10 'and inlet opening 20'. The web 1 is guided between guide rollers 2 to 5, of which at least guide roller 5 is driven by a drive motor 6 the injection device 10 and the suction device 20. The injection device 10 and the suction device 20 have an injection slot nozzle 11 and a suction slot nozzle 21, which are pressed against one another by means of pressing devices 12 and 22 with the interposition of the web 1. As a result, the interior of the injection device 10 is only connected to the interior of the suction device 20 separately by the web 1. In this exemplary embodiment, the interior is essentially sealed off from the outside.

The injection slot nozzle 11 and the suction slot nozzle 21 each have an adjusting slide 13 or 23, which is adjustable via an adjusting motor 14 or 24. The setting is carried out in such a way that the expansion of the slot nozzles 11, 21 in the conveying direction 1 ', that is to say the length L, over which the web 1 is clamped between the edges of the slot nozzles 11 and 21, can be adjusted and adapted if necessary. The length of the slot nozzles 11, 21, that is to say their extension perpendicular to the conveying direction 1 ′ of the web 1 (that is to say perpendicular to the plane of the drawing), is adapted to the width of the web 1. You can do this using the slot nozzles 11,21 telescopically inserted and mutually displaceable elements.

The interior of the suction device 20 is connected to the suction side of a suction pump 25, which sucks the mixture which has passed through the web 1, compresses it and supplies it to a heat exchanger / condenser 26. The condensate coming cooled from the heat exchanger 26 with the residues contained therein and removed from the web 1 is fed from a condensate pump 27 to a washing medium inlet line 33 via a valve 28. The flow rate of the washing medium in the inlet line 33 is sensed via a flow sensor 32, the output signal of which is fed to a control device 7.

Furthermore, the pressure-side output of the condensate pump 27 is connected via a test flow valve 29 to a test device 30 which generates output signals which reflect the state of contamination of the condensate or its concentration of residues taken up. In the exemplary embodiment shown here, the condensate examined is fed back to the inlet line, but can also be discarded since the amount of liquid still required for the examination is small. The feedback valve 28 and the test flow valve 29 are controlled by the central control and regulating unit 7.

The inlet line 33 is connected to a fresh water supply via a fresh water valve 31 controlled by the central control and regulating unit 7 and leads through the heat exchanger 26, so that returned condensate mixed with fresh water can be heated in the heat exchanger 26.

The preheated liquid coming from the heat exchanger 26 is fed to a steam generator 19 which can be heated by means of a heater 18 controlled by the central control and regulating unit 7. In the steam generator 19, a waste water line 9 is provided, via which waste water can be discharged from the steam generator 19 via a valve 17 controlled by the central control and regulating unit 7. This makes it possible to evaporate the returned condensate in the steam generator 19 and to keep it in the steam generator 19 at a consistently high concentration of residues, so that the discharged amounts of waste water are small or the residues removed from the web 1 in the waste water in high concentration attack.

The steam generator 19 delivers steam to the injection device 10 via a steam control valve 16 controlled by the central control and regulating unit 7. In addition, a pump 8 controlled by the central control and regulating unit 7 is provided in order to recirculate the condensate bypassing the steam generator 19 directly to the steam to mix behind the valve. If necessary, another washing liquid or fresh water can also be added here. In this way, the steam can be influenced in its degree of saturation. The admixture is again regulated by the central control and regulating unit 7. Furthermore, a gas, in particular air, is provided for the steam. This is particularly advantageous if, owing to the given conditions on the web 1, large flow quantities per unit of time are necessary.

The central control and regulating unit 7 works here in such a way that the entire washing process is regulated and controlled in accordance with product-specific data that can be input via an input device 34 and treatment-specific data such as the conveying speed. The washing process is monitored in accordance with the output signals of the test device 30 via a display device 35. By continuously monitoring the conveying speed and the flow rate of the returned condensate through the flow rate sensor 32 and the test device 30, it is possible to carry out a real control of the washing process, with the higher-level control loop includes the test device 30. It Not only the steam throughput, but also the length L of the "treatment section" and optionally (in the case of embodiments according to FIGS. 2 and 3) the lengths of the offset sections 54 ', 54 "can be set via the central control and regulating unit 7 such that An important point is that the washing effect is brought about by the action of the steam without the application of additional chemicals.

Instead of measuring the residual substance concentration in the extracted medium (or in addition to this), the concentration of the residual substances remaining on the web 1 after the extraction can also be determined in a residual chemical measuring device 36, which is arranged behind the suction device 20 in the conveying direction 1 'and shown in FIG. 4 is indicated by dash-dotted lines. The measurement signal is fed to the central control and regulating unit 7 via the signal line 37 and used for regulation.

• Breite 41 der Injektionsschlitzdüse 40: lmm
• Dampfdruck: 0,5 bar
• Breite 51" der Absaugschlitzdüse 50": 4mm
• Druck: 15 inches Hg (also ca. 0,5 bar Unterdruck)
• Abstand der Schlitzdüsen 40 und 50" in Förderrichtung 1' von Mitte zu Mitte : 4cm
• Abstand 42 der Injektionsschlitzdüse 40 oberhalb der Warenbahn 1: 1cm

In orientational tests with an arrangement according to FIG. 3, an open towel made of 100% cotton with 25 g / liter indanthrene RS was dyed blue blue. The experimental setup had the following dimensions:

• Width 41 of the injection slot nozzle 40: lmm
• Vapor pressure: 0.5 bar
• Extraction slot nozzle 50 "width 51": 4mm
• Pressure: 15 inches Hg (about 0.5 bar vacuum)
• Distance of the slot nozzles 40 and 50 "in the conveying direction 1 'from center to center: 4cm
• Distance 42 of the injection slot nozzle 40 above the web 1: 1cm

• a) Nur Dampf aufblasen - Effekt gering
• b) Dampf mit 0,5 bar aufblasen und Wasser auf-aufgießen - Effekt gering
• c) wenig Dampf aufblasen und mit 15 inches Hg absaugen - Effekt gering
• d) Dampf mit 0,5 bar aufblasen und mit 15 inches Hg absaugen - Effekt erheblich deutliche Entfärbung (fast weiß)

The following comparative tests were carried out with this test setup with the results given in each case:

• a) Only inflate steam - effect low
• b) Inflate steam at 0.5 bar and pour water on it - effect low
• c) Blow up little steam and vacuum with 15 inches Hg - little effect
• d) Inflate the steam at 0.5 bar and suck it off with 15 inches Hg - the effect is considerably clearer (almost white)

Obviously, it is important that steam is injected with a clear pressure and at the same time suctioned off with considerable negative pressure.

Claims (20)

1. A method of washing a textile web (1) permeable to steam and continuously conveyed in a spread-out position, wherein steam at excess pressure is blown on to the web (1) from one side and the mixture of steam, liquid and residues removed from the web (1) is collected on the other side of the web (1) after passing through it, characterised in that the steam is blown at an excess pressure of at least 0.5 bar and collected on the other side near the blowing site and simultaneously with blowing, using a powerful negative pressure of at least 0.2 bar, in such a manner that large organic molecules for removal from the web are stimulated by the energy supplied by the steam until they decompose or split up, and in this more mobile state they are removed from the web (1).
2. A full-width washing machine for a textile web (1) permeable to steam, comprising

   an injection device (10) having an outlet opening (10') directed from one side against the web (1) and extending over the width thereof,

   a collecting device connected to a pump and having an inlet opening (20') directed from the other side against the web (1), extending over the width thereof, and in the neighbourhood of and opposite the outlet opening (10'), and

   a conveyor for conveying the web (1) between the outlet opening (10') of the injection device (10) and the inlet opening (20') of the collecting device,

   characterised in that
   the collecting device is constructed in the form of a suction device (20) engaging the web (1), and the outlet opening (10') of the injection device (10) and the inlet opening (20') of the suction device (20) are so disposed relative to one another and to the web (1) and the injection device (10) and the suction device (20) are so constructed that steam at an excess pressure of at least 0.5 bar prevailing in the injection device (10) is injected into the web (1) and through the web (1) simultaneously with the injection, at a negative pressure of at least 0.2 bar prevailing in the suction device (20) and extracted from the web (1) in such a manner that large organic molecules for removal from the web (1) are stimulated by the energy supplied by the steam until they decompose or split up, and in this more mobile state they are removed from the web (1).
3. A method according to claim 1 or a full-width washing machine according to claim 2, characterised in that the negative pressure is at least 0.5 bar.
4. A full-width washing machine according to claim 2 or 3, characterised in that the outlet opening (10') and the inlet opening (20') are opposite and overlap one another relative to the plane of the web (1).
5. A full-width washing machine according to claim 2 or 3, characterised in that the outlet opening (10') and the inlet opening (20') are offset from one another in the direction of conveyance (1') of the web (1).
6. A full-width washing machine according to any of claims 2 to 5, characterised in that the extent (41, 51) of the outlet opening (10') and of the inlet opening (20') in the direction of conveyance (1') of the web (1) is the same.
7. A full-width washing machine according to any of claims 2 to 5, characterised in that the extent (51', 51") of the inlet opening (20') in the direction of conveyance (1') of the web (1) is greater than the corresponding extent (41) of the outlet opening (10).
8. A full-width washing machine according to any of claims 2 to 7, characterised in that the outlet opening (10') and/or the inlet opening (20') are slots.
9. A full-width washing machine according to claim 8, characterised in that the outlet opening (10') and/or the inlet opening (20') are defined by slit jets (40, 50; 40', 50'; 40", 50"; 11, 12).
10. A full-width washing machine according to claim 9, characterised in that the slit jets (40, 50; 11, 21) are resiliently pressed against one another with interposition of the web (1).
11. A full-width washing machine according to claim 9 or 10, characterised in that at least one (40) slit jet is at a slight distance (42) from the web (1) at right angles to its surfaces.
12. A full-width washing machine according to any of claims 2 to 11, characterised in that the positions of the outlet opening (10') and/or the inlet opening (20') in the direction of conveyance (1') of the web (1) and at right angles thereto and/or their extents (41, 51, 51', 51") in the direction of conveyance (1') of the web (1) are variable in controllable manner.
13. A full-width washing machine according to claim 12, characterised by an open-loop and closed-loop control device which is connected to the injection device (10), the suction device (20), the steamgenerating device (19) and/or the suction pump (55) and is so constructed that the injection and extraction process is controllable in dependence on parameters of the web (1).
14. A full-width washing machine according to claim 13, characterised in that the open-loop and closed-loop control device is constructed in the form of a central open-loop and closed-loop control unit (7).
15. A full-width washing machine according to claim 13 or 14, characterised in that the injection and/or extraction power, more particularly the flow rate and/or the flow pressure, are controllable in dependence on parameters of the web (1).
16. A full-width washing machine according to any of claims 13 to 15, characterised in that adjusting devices (13, 14; 23, 24) controllable by the open-loop and closed-loop control device are provided and engage the slit jets (40, 50, 50', 50", 11, 21) so as to adjust the extent (41) of the outlet opening (10') and/or the extent (51, 51', 51") of the inlet opening (20').
17. A full-width washing machine according to any of claims 13 to 15, characterised in that the open-loop and closed-loop control device is so constructed that the injection and extraction process is adjustable in dependence on the speed of conveyance of the web (1).
18. A full-width washing machine according to any of claims 13 to 17, characterised in that a test device (30) is provided which is supplied with extracted washing medium and which feeds to the open-loop and closed-loop control device output signals, which correspond to a concentration of residues washed out of the web (1), and the open-loop and closed-loop control device adjusts the injection and extraction process in dependence on the output signals from the test device (30).
19. A full-width washing machine according to any of claims 13 to 18, characterised in that a device (36) for determining the concentration of the residues remaining on or in the web (1) after suction is provided and connected via a signal line (37) to the open-loop and closed-loop control device, which adjusts the injection and extraction process in dependence on the output signals from the device (36).
20. A full-width washing machine according to any of claims 2 to 19, characterised in that devices (18) are provided for supplying the injection device (10) with a gas, particularly air, and/or liquid, particularly water, in addition to steam.

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