EP0105519B1 - 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

3. The invention relates to methods and devices according to the preamble of claims 1 and 3 respectively.

From DE-OS 16 10 233 it is known to suck off the steam produced during drying of the laundry through the roller winding 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 volume, there is generally a negative pressure inside the hollow cylinder (ironing roller) even when there is a high deficiency load, which has the consequence that additional cool air is provided by the free surfaces of the work surface that are not covered by the work surface Roll winding is sucked off. As a result, the hollow cylinder cools down with the roll winding and has to be heated up again in the bow trough.

The same problem also occurs with ironers according to DE-PS 55 416 and GB-PS410522, which suck off the steam from the outside of the roller in some areas, but also cool the iron cylinder by the room air sucked in. To reduce cooling, the GB-PS410522 provides a heating chamber next to the suction chamber, with which the roller winding is heated again. In addition, warm air is supplied through the interior of the hollow cylinder. However, these measures cannot solve the energy problem, since cool room air is still sucked in.

DE-OS 19 37 738, on the other hand, goes one step further by arranging a hood designed as a heat-reflecting reflector above the mangle cylinder, the edge of which on the inlet and outlet sides is sealed off from the roll winding. However, since the steam that forms during ironing has to be extracted axially from the hollow cylinder, cool room air is still sucked in. In addition, this construction requires heat-insensitive bearings of the hollow cylinder with a large diameter and correspondingly high costs. The sealing of the hood, which is designed only as a heat reflector, leads to corrosion during work breaks due to the drop in temperature, which reduce operational safety and require considerable maintenance and expensive precautionary measures.

Starting from DE-OS 19 37 738, the invention is therefore based on the object of achieving better energy savings with simpler and more reliable means.

This object is achieved with the features in the characterizing part of the main method and device claim.

The invention is based on the knowledge that a fundamental energy saving is not only the result. it is possible that the fresh air suction is prevented as much as possible by the free surface of the hollow cylinder which is not enclosed by the bow trough. If, however, the free surface is encompassed by the hood according to the invention in a sealed manner 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 produced during drying can be removed and there is approximately 5 to 7 times the cross-section available, 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, when the deficiency is idling, i.e. with a steam quantity = 0, less false air is sucked in completely through the free roller surface remaining between the hood and the bow trough, unless this can be done by suitable means to prevent.

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 external textile of the roller winding from the outside in and leaves again in the area of the hood from the inside out. This mutual flow through the textile keeps its pores open much longer. In the case of ironers known hitherto, the air is always conducted from the outside inwards through the finishing textile, which acts as a filter for the fluff and dust particles which are abundantly contained in the room air. As a result, the final textile becomes denser and more vapor-impermeable with increasing operating time, which is why it has to be washed more often. The invention avoids these disadvantages.

The teaching according to the invention leads to a new assessment of the alleged need for air to dry the laundry to use pieces in a shortage. Until now, the prevailing view was that the deficiency had to be supplied with a certain amount of air in order to dry the cylinder coverings 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) deal with various possible solutions for 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 the ironing as pure as possible. If you suck this steam off at the inlet side of the hood, 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, troughs or radiators and the hood during its counter-rotating suction movement and overheats as a result, 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 it is possible to carry out a further superheating of the steam.

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.

• Figur 1 einen symbolischen Querschnitt durch eine Muldenmangel mit Abdeckhaube im Leerlaufzüstand,
• Figur 2 einen Querschnitt gemäß Fig. 1 mit eingeführtem Wäschestück,
• Figur 3 einen Querschnitt durch eine mehrere Bügelmulden und Hohlzylinder umfassende Mangel,
• Figur 4 ein Schaubild über den Zusammenhang von Mangel und Waschmaschine und
• Figur 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 :

• FIG. 1 shows a symbolic cross section through a trough lack with a cover hood in the idle state,
• FIG. 2 shows a cross section according to FIG. 1 with the laundry item introduced,
• FIG. 3 shows a cross section through a defect comprising a plurality of bow troughs and hollow cylinders,
• Figure 4 is a graph of the relationship between lack and washing machine and
• Figure 5 is a graph 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 sucked 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, the steam generated by the heating of the laundry 11 on the work surface 5 is sucked 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 from there through the suction nozzle 8 is suctioned off. If the hollow cylinder jacket 2 is perforated, the suction flow also takes place in an 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 fan is then volume-controlled (= speed-controlled) so that the same pressure is always in at different steam quantities the deficiency is maintained.

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 surrounds all the hollow cylinders 2 and accordingly also has only one suction nozzle 8. In this case, the seal 9 is expediently only to be provided on the inlet side on the front hollow cylinder 2 or 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 opposing movement between the item 11 and the suction flow 12. The water vapor generated by the drying of the item 11 initially occurs as saturated steam. In the course of the flow 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.

4 shows an advantageous embodiment for this energy utilization for this purpose. 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, for example, three cylinders 2. The spread out item of laundry 11 is fed via the sealed feed gap 9 to the ironer 1. The saturated steam accumulating during ironing is concentrated in the hood 6 and sucked out from there in the countercurrent principle under overheating 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 laundry item 11 to be dried is pressed by means of a conveyor belt 25 and a plurality of 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 previously 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 a variety of ways. For example, the heating plate 23 can be convex, 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 by the roller axis is used to preheat the air supplied to the ironing bed. This measure, which, as mentioned at the outset, is based on the view that extra air has to be added for the ironing, 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. Existing laundry facilities can also be expanded under Beibe maintenance of the old boiler system. Experiments with the heat recovery method according to the invention and the associated device have shown that the amount of heat supplied to the lack heating 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 only needs to be switched on in cases where insufficient steam is generated in the hood due to a lack of laundry. 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 water vapor generated in the interior 7 of the sealed hood 6 passes through the suction connection 8 into a feed line 15. A separator (not shown) can be arranged in this feed line 15, 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, too few 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 undesired supply of false air. As described above in the description of FIGS. 1 to 3, 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 extraction 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 heating of the washing liquor in the event of an insufficient amount of steam from the ironer 1, the exemplary embodiment in FIG. 4 provides a further auxiliary device in addition to the live steam line 22, which can be arranged instead of or parallel to the live steam line 22. 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. A drop in pressure and external cooling creates a condensate with a temperature of approx. 100 ° C. 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 feed line 15, as a result of which the condensate emits heat to the low-pressure steam from the hood 6. In this way, additional heating of the low-pressure steam can be carried out in the case of an insufficient amount of laundry. On the other hand, this also prevents any residual steam from condensing out in the already insulated feed line 15. The feed 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 (15)

1. A method of mangling, pressing or ironing damp articles of washing between at least one mangling or pressing element, which can be provided with a winding (3) and a heated operative surface (5) which can be brought into contact therewith, the operative surface (5) embracing only part of the area of the mangling or pressing element, while the other remaining part of the area is covered by a sealed hood, and the steam produced during the mangling, pressing or ironing is drawn off, characterized in that the steam produced when passing the operative surface is fed from of the article of washing (11) or the winding (3) while avoiding admixtures of air in the interior (7) of the hood (6) and is drawn off from there through a suction device (8) joined directly to the hood (6).

2. A method according to Claim 1, characterized in that the saturated steam produced during the mangling, pressing or ironing is fed as a driving medium to the washing maschines of the articles of washing to heat them directly by means of compression and where appropriate with intermediate superheating.

3. A mangle, press or the like for performing the method according to Claim 1 or 2, which comprises at least one mangling or pressing element, in particular a rotating hollow cylinder (2) provided with a roller winding (3), and in which the remaining area of the mangling or pressing element not embraced by the operative surface (5) is covered by a hood (6), the edges of which are sealed off from the mangling or pressing element, characterized in that a suction device (8) with a low-pressure blower is connected to the hood (6).

4. A mangle, press or the like according to Claim 3, characterized in that when a plurality of hollow cylinders (2) are arranged serially they are covered by a hood (6) common thereto.

5. A mangle, press or the like according to Claim 3 or 4, characterized in that the suction device (8) is connected to the end area of the hood (6) on the inlet side.

6. A mangle, press or the like according to Claim 3, 4 or 5, characterized in that the suction device (8) is controlled with respect to volume, and a constant balanced pressure or overpressure relative to the atmosphere is set in the hood (6).

7. A mangle, press or the like according to Claim 3 or one of the following Claims, characterized in that the hollow cylinder (2) has a continuous generated surface.

8. A mangle, press or the like according to Claim 3 or one of the following Claims, characterized in that the mangling or pressing element is constructed as a conveyor belt (24, 25) with contact pressure, and the seal (9) is disposed between the hood (6) and the operative surface (5) or a conveyor (18, 25).

9. A mangle, press or the like according to Claim 8, characterized in that the seal (9) is constructed as a sealing lip or as a sealing roller.

10. A mangle, press or the like according to Claim 3, characterized in that the hood (6) is connected to a washing machine (17) by way of a supply line (15) with a compressor or blower (19).

11. A mangle, press or the like according to Claim 10, characterized in that the supply line (15) opens as a direct heating means into the washing liquor of the washing machine (17).

12. A mangle, press or the like according to Claim 10, characterized in that a pressure sensor (13), which is connected by way of a controlled system to a throttle valve (14) or the blower (19) in the supply line (15), is disposed in the hood (6).

13. A mangle, press or the like according to Claims 10 and 11, characterized in that parallel to the supply line (15) a live steam line (22) and/or a condensate line (21) from the mangle heating means open into the washing machine (17).

14. A mangle, press or the like according to Claim 13, characterized in that the supply line (15) and the condensate line (21) are guided at least in steps in heat-exchanging contact with one another.

15. A mangle, press or the like according to Claim 10, characterized in that an hermetically sealable ventilation flap is disposed in the hood (6).

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