EP0105519A1 - Method and apparatus for calendering damp linens - Google Patents

Abstract

PCT No. PCT/EP83/00257 Sec. 371 Date Jun. 4, 1984 Sec. 102(e) Date Jun. 4, 1984 PCT Filed Oct. 3, 1983 PCT Pub. No. WO84/01395 PCT Pub. Date Apr. 12, 1984.In the case of common trough mangles (1) used for the smoothing and drying of wet laundry pieces (11) wherein the hollow rollers (2) provided with roller wrappings (3) are only partially surrounded by heated pressing troughs (4, 5), a considerable amount of energy is wasted due to the absorption of cooler room air. In order to eliminate the cause of this deficiency, the invention proposes to cover the free area of the hollow roller (2) with a hood (6), whose rims (9) are sealed against the roller wrapping (3). The exhaust (8) of the steam is removed directly from the hood (6). This way, inside the hood (6) clean saturated steam is obtained and superheated, when the absorption from the hood (6) takes place in counterflow with regard to the travel of the laundry pieces (11). This superheated saturated steam is especially suitable as operating means for washing machines or the like.

Description

The invention relates to methods and devices for ironing damp laundry items which are conveyed between at least one perforated hollow cylinder provided with a roller winding, rotating and connected to a suction device and a heated work surface in the form of a trough-shaped hollow body which can be brought into contact with it the working surfaces encompass only a partial area of the hollow cylinder and the other partial area is covered by a hood which is sealed off from the roller winding.

In the case of the usual lack of troughs, the padded hollow cylinders are enclosed by the work surfaces in a circumference of less than 165 °. The steam generated during the drying of the laundry is extracted by the roller winding and a large number of bores in the steel jacket of the hollow cylinder via a blower connected at the end. These blowers must be designed in such a way that they can cope with the amount of steam generated at maximum deficiency utilization. Since they are dimensioned with a safety factor with regard to the delivery head (negative pressure) and delivery rate, there is generally a negative pressure inside the hollow cylinder (ironing roller) even when there is a high deficiency load, which means that additional cool air is provided by the free surface not covered by the work surface the roll winding is suctioned off. This free surface covers approximately 195 ° of the roll shell.

If the shortage is supplied with little or no laundry at all, then with the help of the suction, which is mostly independent of the rotational speed of the hollow cylinder, one has to accept the considerable disadvantage of an energy destruction machine. Because in this case, only room air is sucked through the rotating hollow cylinder, cools it on the way from the exit from the ironing bowl to re-entry and thus reduces the effective drying speed by about 10 to 15%, on the other hand, while heating the Required energy in the form of steam must also be supplied to the air trough.

To dry 1 kg of laundry with normal residual moisture, a steam quantity of 1.2 kg and more is required for heating the ironer at the degree of occupancy of 40 to 60% that is usual in practice. The thermal efficiency is about 50% or less.

Numerous proposals for reducing the energy consumption of such conventional ironers have been published. For example, attempts have been made to cover the free area of the roll winding with a shell which extends approximately 3 cm from and parallel to the surface of the roll winding. A slight reduction in energy consumption is possible because the unhindered heating of the room air on the hot surfaces of the top of the ironer as well as the heat radiation are reduced. Because the shell is at a distance from the roller coating, the large opening slots on the inlet and outlet side, which have a cross-section of approximately 1 square meter, allow the the same amount of room air is extracted as with fully exposed ironing rollers. The amount of room air is then unnecessarily blown into the open as hot air. Since the cross-section of the suction connection on the ironing roller is considerably smaller than the cross-section of the opening slots mentioned, the surface of the ironing roller is disadvantageously supplied with room air.

DE-OS 19 37 738 tries to avoid this disadvantage by sealing the edge on the inlet and outlet sides of a shell designed as a hood with a reflector against the roller winding. However, since the steam that forms during ironing has to be extracted axially from the drum, the formation of heat-insensitive bearings with a large diameter and correspondingly high costs is inevitable. The sealing of the hood with respect to the roller winding leads to corrosion when work is interrupted due to the drop in temperature, which requires considerable additional effort by suitable countermeasures to avoid it.

The invention is therefore based on the object to achieve the desired energy savings in a cost-saving manner and to use the energy saved more profitably.

This object is achieved with the method according to the invention in that the water vapor generated when passing through the work surface is led out of the laundry or the roller winding into the interior of the hood and is drawn off from there by a suction device directly connected to the hood.

A special embodiment of the invention, which can have an independent character, is that the If there is a lack of saturated steam with the best possible exclusion of air admixtures as the operating material, the washing machines of the laundry items are supplied for direct heating by means of compression and, if necessary, with interim overheating.

The invention is based on the knowledge that a fundamental energy saving is not only possible by preventing the fresh air extraction as much as possible by means of the free surface of the hollow cylinder which is not enclosed by the bow trough. If, however, the free surface of the hood according to the invention is sealed and connected to the suction device, the volume output of the suction fan can be reduced to 60%. The suction of the water vapor produced during drying can therefore be carried out directly from the hood, since in the usual spring press and elastopress spring wraps of the hollow cylinder there is a sufficiently large suction cross-section between the molton cover and the roll shell. It is therefore entirely possible to make the jacket of the hollow cylinder unperforated. If, on the other hand, a perforated cylinder jacket is used, but without an axial suction nozzle, then the suction of the water vapor through the hood is made even easier. Since in the case of direct suction according to the invention almost only the steam generated during drying can be removed and about 5 to 7 times the cross-section is available for this purpose, the negative pressure to be provided by the blower can be greatly reduced to about 35% of the previous negative pressure.

A low-pressure blower can therefore be used with the advantage that the deficiency, that is to say a steam, when idling quantity = 0, less false air is sucked in through the free roller surface remaining between the hood and the bowl depression, unless suitable means can be used to completely prevent this.

A considerable cost saving also lies in the fact that the axial connection of the suction to the hollow shaft of the hollow cylinder, which is customary in known systems, can be dispensed with, which leads to a smaller and therefore cheaper mounting of the hollow cylinder.

An advantage of a different kind arises with regard to the direct suction of water vapor from the hood in that the steam accumulating in the trough area penetrates the outer textile of the roller winding from the outside in and leaves again in the area of the hood from the inside out. This mutual Dutch flow of the textile keeps its pores open much longer. In the case of ironers known hitherto, the air is always passed from the outside inwards through the finishing textile, which acts as a filter for the fluff and dust particles which are abundant in the room air. Thus the conclusion textile with increasing operating time is getting closer and dampfundurch- l _ä FLOWING, so it must be washed frequently. The invention avoids these disadvantages.

The teaching according to the invention leads to a new assessment of the alleged need to use air to dry the laundry in a defect. So far, the prevailing view was that the deficiency had to be supplied with certain amounts of air in order to dry the cylinder wrapping covers and to be able to transport the steam generated during ironing. Even the latest proposals (DE-OS 30 44 229, DE-OS 31 23 886, DE-OS 32 09 365) be sum up with different solutions how to supply air to the shortage.

The invention turns away from this, since it strives to keep air away, if possible, or even to remove it, in order to maintain and utilize the steam produced during ironing as pure as possible. If you suck this steam off at the inlet side of the hood, then there is already superheated steam, while saturated steam is still present on the opposite side of the hood. The superheating of the steam preferably results from the countercurrent principle, according to which the items of laundry pass the mangle contrary to the steam suction flow. The saturated steam initially formed during ironing sweeps over heated metal parts of rollers, hollows or radiators and the hood during its counter-suction movement and overheats, which in turn leads to drying of the roller covers with superheated steam. Surprisingly, it has been shown that air does not have to be added as drying and transport means at all, but rather that an air supply would be harmful.

The superheated steam generated in the manner of ironing in accordance with the invention is fed to the washing machines as operating means for direct heating in the sense of an exemplary embodiment of the invention, for which purpose the steam can optionally be further overheated.

A comparative energy calculation has shown that about 50% fresh steam can be saved for supplying the washing machine and the lack of steam with steam, if the washing machine is fed from the superheated steam produced during the ironing.

In summary, using the method according to the invention, the drying speed can be increased, the energy saving can be significantly improved and the thermal efficiency can be increased significantly. There is a much shorter heating-up time of the ironer using less heating energy. The heat output to the room is significantly reduced, as is the idle consumption. In order to bring about these savings, it is not necessary to use the expensive heat exchangers required in the prior art.

Suitable devices for carrying out the method according to the invention are defined in the subclaims.

• Fig. 1 einen symbolischen Querschnitt durch eine Muldenmangel mit Abdeckhaube im Leerlaufzustand,
• Fig. 2 einen Querschnitt gemäß Fig. 1 mit eingeführtem Wäscheatück,
• Fig. 3 einen Querschnitt durch eine mehrere BUgelmulden und Hohlzylinder umfassende Mangel,
• Fig. 4 ein Schaubild Über den Zusammenhang von Mangel und Waschmaschine und
• Fig. 5 ein Schaubild einer Flachpresse zur Verdeutlichung der Anwendung der Erfindung auf andere Wäschebehandlungsmaschinen.

Embodiments of the invention are shown schematically in the drawing. Show it:

• 1 is a symbolic cross section through a trough lack with cover in the idle state,
• 2 shows a cross section according to FIG. 1 with the laundry item introduced,
• 3 shows a cross section through a defect comprising several bow troughs and hollow cylinders,
• Fig. 4 is a graph on the relationship between lack and washing machine and
• Fig. 5 is a diagram of a flat press to illustrate the application of the invention to other laundry treatment machines.

The basic structure of the invention can be seen from the example of FIG. 1, where the trough lack is designated by 1. This has a rotatably mounted and driven hollow cylinder 2, which does not need to have roller perforations, but can also be provided with such perforations. This hollow cylinder 2 is surrounded by a roller winding 3, which is designed in a conventional manner. A partial area of the roller winding 3 is encompassed by a trough-shaped hollow body 4, which has a heated working surface 5, via which the thermal energy for drying and smoothing the laundry item 11 is applied.

The area of the hollow cylinder 2 or its roller winding 3 which is not covered by the trough-shaped hollow body 4 is encompassed by a hood 6, the interior 7 of which is sealed off from the roller winding 3 by means of seals 9. An extraction nozzle 8 is connected to the hood 6.

As shown in FIG. 1, the room air can reach the roller winding 3 in a minimal amount along the narrow air supply 10, through the interior of which the air enters the interior 7 of the hood 6 and is extracted from there. It is therefore sufficient to use a low-pressure blower so that when the idle runs, the shortage, that is to say no steam, little false air is drawn in through the free roller surface located between the hood 6 and the trough 4.

If, on the other hand, as shown in FIG. 2, a piece of laundry 11 is in passage, then practically only a negligible minimum amount of false air is drawn in. Instead, it is caused by warming of the laundry item 11 on the working surface 5, steam is drawn in accordance with the flow arrows 12 from the interior of the roller winding 3, from which the steam, due to its expansion, easily reaches the interior 7 of the hood 6 and is sucked out from there through the suction connection 8. If the hollow cylinder jacket 2 is perforated, the suction flow also takes place in the approximately radial direction through the hollow cylinder 2.

By setting certain pressure ratios, surprising effects can be achieved.

With equal pressure or even a slight excess pressure in the hood 6 relative to the surroundings, it is possible to completely exclude the false air. The blower is then volume-controlled (= speed-controlled) in such a way that the same pressure is always maintained in the ironer with different steam quantities.

3 has a plurality of hollow cylinders 2 and trough-shaped hollow bodies 4, then it is expedient to provide a single hood 6 which encompasses all the hollow cylinders 2 and accordingly also has only one suction nozzle 8. In this case, the seal 9 is expediently provided only on the inlet side on the front hollow cylinder 2 or on the inlet conveyor and on the outlet side on the rear hollow cylinder 2 or on the outlet conveyor.

The suction nozzles 8 are advantageously arranged on the inlet side of the hood 6. This results in an opposite movement between the laundry 11 and the suction flow 12. The water vapor generated by the drying of the laundry 11 initially occurs as saturated steam. In the course of the current 12 this saturated steam heats up on heated bare metal parts and is available in the area of the suction nozzle 8 as a high-quality energy source.

For this purpose, FIG. 4 shows an advantageous exemplary embodiment for this energy utilization. A washing machine 17, which requires energy and heat for its washing work, is connected via a conveyor 18 to the ironer 1, which can have three cylinders 2, for example. The spread out item of laundry 11 is fed via the sealed feed gap 9 to the ironer 1. The saturated steam that accumulates during ironing is concentrated in the hood 6 and is sucked out from there in the countercurrent principle under superheating at 8.

FIG. 5 shows an alternative to FIGS. 1, 2 and 3. The drying method according to the invention is not only suitable for ironing, but generally for contact drying. 5 shows a contact press 26, which has a flat heating plate 23, on which the item of laundry 11 to be dried is pressed by means of a conveyor belt 25 and several pressure rollers 24. The contact press 26 is surrounded on the outside with the hood 6, the interior 7 of which is secured by seals 9 against entry of false air. In this exemplary embodiment, as also in the above-described embodiments, the hood 6 is of course not only sealed in the conveying direction, but also to the side, for example against the hollow body 4 or the heating plate 23. The conveyor belt 25 has recesses through which the water vapor can escape from the laundry into the hood interior 7 and from there through the suction nozzle 8.

Variations of the contact press 26 are possible in many different ways. For example, the heating plate 23 can be convexly curved be, which saves the pressure rollers 24. Likewise, it can also be a so-called ironing press, in which a padded cushion, similar to the roller winding 3 (FIG. 1 with 3), is placed against the item of laundry and presses it against an arbitrarily shaped heating plate.

Fig. 5 also shows a variation of the seals 9. The left seal of the hood 6 is designed as a roller seal, which is pressed against the deflection roller of the conveyor belt 25. The roller seal consists of a flexible or liftable, sealing roller, which is particularly advantageously arranged on the inlet side of a mangle or another contact press. It is also possible to position the roller seal against the deflection roller of the infeed conveyor 18 (in FIG. 5) and to lift it briefly when a piece of laundry arrives. Of course, such a roller seal can also be arranged on the outlet side of the machine.

In FIG. 5, a lip seal 9 which differs from FIGS. 1 to 3 is also arranged on the outlet side of the contact press 26. This lip seal rests against the running laundry 11 or the heating plate 23.

The all-round sealing of the hood 6 leads to the fact that its interior is only filled with water vapor when ironing, ironing, pressing or the like. The water vapor present at the suction nozzle 8 represents a high-quality energy source that must be used in the sense of energy saving.

In the prior art, the water vapor drawn off through the roller axis is used to preheat the air supplied to the mangle bed. This measure, which, as mentioned at the outset, is based on the view that extra air must be added to the ironer, is not a satisfactory energy saving measure.

In further training of the main task, a possibility for a better use of the steam is to be shown.

To achieve this object, the invention proposes to supply the highly concentrated water vapor, which contains only a negligible amount of air, via a line to the upstream washing machine and to heat the washing liquor directly with the steam introduced.

This measure can also be used with ironers, ironing machines or presses according to the prior art, if only with little success. The highly concentrated water vapor from the sealed hood has the great advantage that, when introduced into the wash liquor, it emits its thermal energy practically without loss. This is due to the fact that the heat exchange between water vapor and water is more efficient than the heat exchange between warm air and water.

In addition to the fresh water consumption for direct heating of the washing liquor with live steam, the method of heat recovery according to the invention also reduces the energy costs associated with steam generation. A separate boiler is no longer required for direct heating of the washing liquor, or an existing boiler can be made smaller. Likewise, existing laundry facilities can be expanded while maintaining the old boiler system. Experiments with the heat recovery process according to the invention and the associated device have shown that the amount of heat supplied to the lack heater is completely sufficient to generate and remove so much water vapor in the hood that the washing liquor alone can be heated with it. An additional heater for the washing machine is only required in cases where insufficient steam is generated in the hood due to a lack of laundry to be turned on. Such additional heaters can be designed in any form as an electric heater, as a live steam heater or the like.

Fig. 4 shows the heat recovery method according to the invention and the associated device. Wet laundry 11 is transferred from a washing machine 17 to a conveyor 18 and is dewatered mechanically, for example, by a device (not shown). From the conveyor 18, the laundry 11 arrive in the ironer 1 via a known infeed conveyor. The ironer 1 can of course also be an ironing machine, a press or the like. The interior 7 of the sealed hood 6 resulting water vapor passes through the suction nozzle 8 into a supply line 15. In this supply line 15 a separator (not shown) can be arranged, which separates the water vapor from any entrained air. In the further course of the feed line 15, a compressor or a high-pressure fan 19 is arranged, which conveys the water vapor and presses further through the line into the washing liquor of the washing machine 17. For the start-up phase of the system, when no laundry has been ironed, pressed or ironed and therefore no steam is available, a live steam line 22 which can be switched off and which opens into the washing liquor is provided. As soon as sufficient steam is available in the hood 6, this live steam line 22 is switched off.

Fluctuations in the degree of loading can occur during the operation of such a washing system. In such a case, there are then, for example, little or no laundry items 11 in the ironer 1 and accordingly little or no water vapor is generated in the hood 6. However, the compressor or the blower 19 still suck to the same extent, which means that a Negative pressure can arise in the hood interior 7, which leads to an undesirable False air supply leads. As described above in the description of FIGS. 1 to 3, however, the aim of the hood seal is to generate at least the same or a slightly higher pressure in the hood interior 7 than outside the hood 6.

In order to be able to automatically regulate the steam suction according to the available amount of steam, a pressure sensor 13 is provided in the hood interior 7, which registers the internal pressure and acts upon a throttle valve 14 in the supply line 15 when the value falls below a predetermined value and thus reduces the suction pressure that is present. Instead of the throttle valve 14, the compressor or the blower 19 can also be regulated. As soon as the hood internal pressure rises again by supplying laundry items, the suction pressure is automatically increased.

In order to ensure that the washing liquor is heated in the event of an insufficient amount of steam from the ironer 1, the exemplary embodiment in FIG. The trough-shaped hollow body 4 or a differently designed heating plate is thereby heated under high pressure steam, which is supplied from an external boiler (not shown) via a steam line 20. With such a high-pressure steam heating, condensate occurs at a temperature of, for example, 180 ^° C., which is led back to the outside via a condensate line 21. Due to the drop in pressure and external cooling, a condensate with a temperature of approximately 100 ° C. is produced here. The condensate line 21 can now open directly into the washing machine 17 and serve to start the wash liquor. In addition, this condensate line 21 is also guided in or around the supply line 15, whereby the condensate transfers heat to the low-pressure steam from the hood 6 gives. In this way, additional heating of the low-pressure steam can be carried out in the case of insufficient laundry. On the other hand, this also prevents any residual steam from condensing out in the already insulated feed line 15. The supply line 15 also has a drain 16, by means of which it can be drained if necessary.

In connection with the heat recovery, it is advisable to make the sealed hood 6, which otherwise corresponds to the exemplary embodiments of FIGS. 1 to 3 and 5, particularly large. This has the advantage that, in the event of fluctuations in the loading of laundry items, the large hood interior 7 acts as a buffer for the steam discharge and prevents the suction pressure from being readjusted too frequently.

A lockable ventilation flap (not shown) is arranged in the hood 6 and is opened shortly before the ironer, ironing press or the like is stopped. This air supply, in conjunction with the fan 19 that continues to run, allows the steam contained in the hood 6 to be completely sucked off, which could otherwise condense out and be reflected in the defect. In normal operation, the ventilation flap is of course hermetically sealed.

Claims (16)

1) Method for mangling damp laundry items which are conveyed between at least one perforated hollow cylinder provided with a roller winding, rotating and connected to a suction device and a heated work surface in the form of a trough-shaped hollow body which can be brought into contact with the work surface, the work surface being only a partial area of the hollow cylinder and the other partial area is covered by a hood that is sealed with respect to the roller winding, characterized in that the water vapor generated when passing through the working surface from the laundry item (11) or the roller winding (3) into the interior (7) of the hood ( 6) and withdrawn from there by a suction device (8) directly connected to the hood (6). 2) Method according to claim 1, characterized in that the saturated steam obtained during ironing while largely avoiding air admixtures as operating equipment is fed to the washing machines of the laundry items for direct heating by means of compression and, if appropriate, with interim overheating. 3) Shortage for performing the method according to claim 1 or 2, in which the area of the hollow cylinder which is not enclosed by the working surface is covered by a hood, the edges of which are sealed against the roll winding, characterized in that a suction device (8) is connected to the hood (6). 4) Deficiency according to claim 3, characterized in that when a plurality of hollow cylinders (2) are arranged in rows, these are covered by a hood (6) common to them. 5) Deficiency according to claim 3 or 4, characterized in that the suction device (8) is connected to the inlet-side end region of the hood (6). 6) Application of the invention to other machines and devices for drying, ironing, pressing or the like. Treating wet laundry items. 7) lack or the like. According to claim 3 or one of the following, characterized in that the seal (9) between the hood (6) and the work surface (5) or a conveyor (18, 25) is arranged. 8) lack or the like. According to claim 7, characterized in that the seal (9) is designed as a sealing lip or as a sealing roller. 9) lack or the like. For carrying out the method according to claim 2, characterized in that the hood (6) via a feed line (15) with a compressor or blower (19) is connected to a washing machine (17). 10) Defect or the like according to claim 9, characterized in that the feed line (15) opens as direct heating in the washing liquor of the washing machine (17). 11) Defect or the like according to claim 9, characterized in that a pressure sensor (13) is arranged in the hood (6), said pressure sensor (13) over a controlled system with a throttle valve (14) or the blower (19) in the feed line (15) connected is. 12) lack or the like. According to claim 9 and 10, characterized in that parallel to the feed line (15) a live steam line (22) and / or a condensate line (21) from the lack heater in the washing machine (17) open. 13) Deficiency or the like. According to claim 12, characterized in that the feed line (15) and the condensate line (21) are guided in heat-exchanging contact with one another at least in part. 14) lack or the like. According to claim 9, characterized in that an airtight lockable ventilation flap is arranged in the hood (6). parts list 1 lack 2 hollow cylinders 3 roller winding 4 trough-shaped hollow body 5 work surfaces 6 hood 7 interior 8 extraction nozzles 9 sealing 10 air supply 11 items of laundry 12 flow 13 pressure sensors 14 throttle valve 15 supply line 16 indulgence 17 washing machine 18 sponsors 19 compressors, blowers 20 steam pipe 21 condensate line 22 Live steam line 23 heating plate 24 pinch roller 25 conveyor belt 26 contact press

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