EP1205592B1 - Laundry dryer cabinet - Google Patents

Abstract

The cabinet has a drying chamber (1) and an equipment part (3) with a heat pump consisting of an evaporator unit (15), a compressor (27) and a condenser (25) and an air circulating element (35). At least one additional air channel in the equipment part enables at least some circulated air to pass at least approximately unhindered through the equipment part to be fed into the dryer chamber again at least approximately untreated. Independent claims are also included for the following: a method of operating a washer-dryer cabinet and a use of the dryer cabinet for textiles and similar materials, fabrics and materials containing fabric.

Description

The present invention relates to a dryer cabinet or also called drying cabinet with a dryer room and an apparatus part with a heat pump, consisting of an evaporator unit, a compressor and a condenser and with a recirculating air generating member for generating the air circulation in the cabinet, a method of operation a drying cabinet, and its use for drying textiles and other goods.

From CH-A-672 836 a two-part tumble dryer cabinet is known, in which the drying of the wet laundry takes place with a closed air circuit. This closed air circuit has proved to be disadvantageous in that by operating the heat pump, a successive heating of the air takes place, which either an increasing power of the cooling unit or the heat pump is required or decreases the efficiency of the drying process with progressive duration of the drying operation. The consequence of this is a high energy consumption and an overheating of the heat pump.

A solution is proposed in the Swiss Patent 690 038 by the air circuit is not performed closed, but by means of a supply air fan air is supplied from outside the circuit. This additionally supplied air is added to the already dried air, heated in the condenser of the heat pump and fed to the drying room of the cabinet. The resulting excess air is discharged immediately after the exit of the still warm and moist air from the oven to the environment. Due to the temperature difference from the incoming air and the re-discharged additional air quantity is achieved that a continuous heating of the closed air circulation circulating air is avoided and the efficiency of the system can be maintained. The disadvantage is that the apparatus part is complicated and expensive, but at least two fans are to operate, creating a higher energy consumption and higher moisture emission is generated in the surrounding space.

From EP 0 467 188 a tumble dryer is also known with an open air circuit, similar to the solution proposed in the Swiss patent application CH 1275/96. In contrast to the Swiss patent application mentioned here, the resulting excess air is released back to the environment after heating by the condenser and before entering the drying cabinet, which in contrast to CH 1275/96 in EP 0467188 warm and dry air the environment is released. The advantage is that on the one hand the environment, such as a basement, does not get wet and, moreover, heating of the quasi-closed air circuit in the drying cabinet can be avoided. The disadvantage, however, lies in the relatively small amount of air which is passed through the drying room, which can lead to an extension of the drying process.

Further, from DE 3 407 439 and GB 2 002 891 proposals are known to provide in the circulation or recirculation of the hot air, a cooling unit to extract at least a portion of the moisture of the drying air before reintroduction into a drying room. In DE 4 306 250 an additional heat exchanger is provided to perform a heat exchange directly in the process air stream. In GB 2 092 729 in turn, the heat of the exhaust air is used to heat by means of heat exchanger fresh air. Finally, it is proposed in DE 3 446 446 to dry in a closed circuit only a part of the circulating air and to guide the rest in the sense of a so-called bypass and to add the dried part for reintroduction into the drying room.

In the German Utility Model DE 82 23 089 Finally, a heat-air unit for drying systems is described in which exhaust air is partially recycled and mixed with supply air to be added by a blower and a heater back to a drying oven.

It is an object of the present invention to propose a drying cabinet which also has an open air circuit without the disadvantages of the solutions proposed in particular in CH-PS 690 038 and EP 0 467 188.

According to the invention a drying cabinet according to the wording of claim 1 is proposed, and according to claim 7, a method for operating this drying oven and according to claim 15, the use of the cabinet or the method for drying textiles.

As already known from EP 0 467 188, air from outside the circulating drying air between the evaporator and the condenser is additionally added here in the apparatus part, but the excess amount of air thus obtained is added not returned to the environment after heating by the condenser and before entering the dryer cabinet, but only after passing through the dryer room, immediately after leaving the dryer room, as proposed in CH 1275/96. In contrast to the two solutions in EP 0 467 188 and CH 1275/96, it is proposed according to the invention that an additional air duct is arranged in the apparatus part in order to guide part of the warm and moist air escaping from the dryer space through the apparatus part, so that this is partially recycled untreated back into the dryer room. This additional air guide is such that a portion of the air circuit is recirculated in direct bypass of the evaporator and the condenser through the apparatus part. The advantage of this additional air guide is that with substantially the same device for the generation of the air circuit, a substantially increased air flow through the dryer room or the dryer cabinet can be generated as for example in the proposed devices, known from the prior art. This increased air flow in the dryer room leads to increased movement of the dry material, whereby the drying process can be significantly accelerated. Another advantage of this solution is that only a relatively small part of the moist, heated air is released to the environment, but sufficient to prevent heating of the quasi-closed air cycle in the drying cabinet. However, the amount of air discharged to the environment is so small in relation to the total amount of air that the increase in humidity in the ambient space in which the drying cabinet is, is marginal. Another major advantage of the additional air guide proposed by the invention, which is a "bypass" air duct, lies in the fact that with only one air circulation generating organ or a single fan increased air circulation in the dryer cabinet can be achieved.

The amount of air in this so-called "bypass" air flow can either be chosen to be substantially constant throughout the drying process or else variable or controllable. In particular, with constant bypass air flow management results in the important advantage that can be dispensed with an additional control and regulatory body.

The inventively proposed bypass air duct can be formed both in one or two parts by the at least partially untreated, moist and warm air from the outlet from the dryer room practically until re-entry into the dryer room separated from the devices arranged in the apparatus part, such as evaporator, condenser etc .. ., to be led. Or the said amount of air is mixed after passing through the evaporator with the air cooled and dried there, whereupon the mixed air thus obtained is again separated before passing through the condenser to reheat the air, so that a part is conducted separately from the condenser and the other part through the capacitor. It is essential in both cases that a part of the recycled and closed air circulation passes through the apparatus part largely unhindered, whereby a larger amount of air can be conveyed with constant power of the device responsible for air circulation.

According to a further preferred embodiment of the present invention, it is proposed that in the apparatus part upstream of the evaporator, a heat recovery unit is arranged, such as a so-called plate heat exchanger, in which in countercurrent or cross-flow part of the discharged from the dryer cabinet moist and warm air and the be passed through the evaporator cooled and dried air. It can thereby be achieved that in the plate exchanger the cooled and dry air through the evaporator part of the moist and warm air from the dryer cabinet already pre-cools or pre-dehumidified and thus the total power required in the heat pump or in the cooling unit can be reduced. On the one hand, the cooling capacity of the evaporator can be reduced and on the other hand, the heating power in the condenser, since in the invention proposed heat recovery (WRG) unit on the one hand a part of the moist, warm exhaust air from the dryer cabinet is cooled and on the other hand, the part corresponding cool, dry air itself already warmed up a bit again. Another major benefit of using this heat recovery unit is that as the duration of the drying operation increases, the performance of this recovery unit is increased by increasing the temperature difference between the warm, humid exhaust air from the dryer cabinet and the cooled, dry air. This results in comparison to the dryer cabinet, known from the prior art, the further great advantage that the per se increasing power consumption of the heat pump during the drying process significantly lower when using this heat recovery unit, such as the mentioned heat recovery plate exchanger.

In conclusion, on the one hand results in a much better efficiency of the drying unit and associated with a reduction in the required drying time and a much lower energy consumption than in the known today from the prior art drying cabinets.

The invention will now be explained in more detail by way of example and with reference to the accompanying drawings.

Fig. 1

einen Trocknerschrank der bekannten Art in Vorderansicht;

Fig. 2

eine Vorderansicht der Wärmepumpe bzw. des Apparateteils des Trocknerschrankes mit entfernter Frontabdeckung;

Fig. 3

eine Ansicht von oben der Wärmepumpe bzw. des Apparateteils des Trocknerschrankes mit entferntem Deckel, und

Fig. 4

den Schnitt des Apparateteils aus Fig. 2 entlang der Linie B-B.

Showing:

Fig. 1

a drying cabinet of the known type in front view;

Fig. 2

a front view of the heat pump or the apparatus part of the dryer cabinet with the front cover removed;

Fig. 3

a top view of the heat pump or the apparatus part of the drying cabinet with the lid removed, and

Fig. 4

the section of the apparatus part of Fig. 2 along the line BB.

FIG. 1 shows a drying cabinet 1 with a door opening 2 and latches 4. Above the actual drying room, a device part or a heat pump 3 provided with a front cover is arranged, which front cover can be closed, for example by means of square locks 5. Arranged in this front cover is also an operating display 7 and an air inlet opening 21, whose operation will be discussed later. In the lid 6 of the dryer cabinet, an air outlet opening 36 is arranged, whose operation is also discussed below.

FIG. 2 now shows the heat pump arranged above the dryer space 1 or the apparatus part 3 with the front cover removed, so that the individual components of the heat pump are visible.

The actual heat pump consists of a heat recovery unit, such as a plate exchanger 14, an evaporator 15, a condenser 25 and a compressor 27. Via connecting lines 28, 29 and 31 are the, the actual heat pump forming Units for transporting the cooling medium connected to each other.

Provided for generating the air circulation is a fan 35, and for generating the inventively proposed bypass air flow 18 respectively. 32, on the one hand, an air passage 12 and a further air passage 30 are provided.

Based on the heat generated in the heat pump or in the apparatus part and passing through the air stream, which is shown schematically by dashed lines, will be discussed in more detail on the operation and the individual elements. From the dryer room 1 enters moist and warm air 11 through a so-called lint filter 13 into the apparatus part 3 a. This so-called lint filter is necessary to prevent clogging of the cooling unit by fibers, dust, lint and the like.

Part of the moist and warm exhaust air 11 now passes first through the plate exchanger 14, is pre-cooled or pre-dehumidified, to be subsequently further cooled in the evaporator 15 and dehumidified. The thereby condensing water from the air is collected in a pan or gutter, not shown, and discharged outside the dryer cabinet.

The thus cooled and dehumidified air 16 is recirculated and passed again across the hot and humid exhaust air flow 11 through the plate exchanger 14 to be heated itself, and on the other hand to pre-cool or pre-dehumidify the warm and moist exhaust air.

Another portion of the moist and warm air 11 is passed through the air passage 12 untreated, to form a first bypass air flow 18, which again with the Plate exchanger guided and heated air 16 is mixed. The thus-formed mixed circulation air 17 is mixed at an excessively high dryer room temperature at the air inlet opening 21 with additional air 19 from outside. The main part 23 of this mixed air is then passed through the condenser 25 and thereby heated. The other part of this mixed air is passed through a second air passage 30 to form the second air bypass 32. This bypass air quantity 32 as well as the mixed air 33 heated by the condenser 25 is sucked in by the fan 35 and, after passing through the fan through an air grille 38, is supplied to the dryer space 1 as heated and relatively dry air 39. The humidity of the air supplied to the dryer chamber 39 may well be slightly higher than the corresponding humidity in supply air in drying cabinets, known from the prior art, but this is not a disadvantage due to the increased air flow. On the contrary, the drying efficiency is increased in the dryer room by the increased amount of air which is passed through the dryer room, since the drying material located in the dryer room, such as clothes, is moved more intensively or the air flow is at least partially turbulent.

The separation or foreclosure plate 22 arranged centrally in the heat pump or in the cooling unit or apparatus part 3 generates the deflection of the air flow for the second throughflow of the plate exchanger.

FIG. 3 shows the heat pump or the apparatus part 3, seen from above, with the lid lifted off, so that the individual apparatus units are visible. In this case, a repetition of the individual parts of the apparatus can largely be dispensed with, since one and the same apparatus parts are provided with the same reference numerals. It should be noted that the two air openings 12 and 30 are shown only hinted dashed, since they are only poorly representable in top view.

Finally, FIG. 4 shows in section the apparatus part along the line BB from FIG. 2, viewed in the direction of the condenser 25. The air inlet opening 21 for supplying air from outside as well as the air passage 30 for the formation of the second bypass opening are clearly recognizable. air flow.

From the schematic representation of the heat pump or the apparatus part in Figures 2 to 4 clearly shows the apparatus and design simple design of the heat pump or apparatus part. Particularly striking in comparison with drying cabinets, known from the prior art is that only a circulation-generating member, such as a single fan 35, must be used, which results from the very simple management of the so-called bypass air flow. In addition, the performance of this fan 35 can be kept relatively low, since the "closed" air flow to be recycled is guided in part through the apparatus part partly in parallel via the two bypass air ducts. This is also reflected in lower power consumption. In the further clearly recognizable is the fact that only relatively little moist warm air is released to the environment and not, as in known drying cabinets, large amounts of moist, warm air, which can lead to an unpleasant increase in humidity in the environment.

The bypass airflow may be operated at a constant rate, such as about 20% -30%, based on the total amount of airflow circulating within the apparatus section 3. So it is possible, for example, with a total amount of air flow within the apparatus part 3 of circa 850 - 950 m ^{3 of} circulating air circulating air flow of about 150 - 250 m ³ as a bypass airflow 18 resp. 32 feed. When operating the dryer cabinet proposed according to the invention, it is possible, in particular at the beginning of a new drying phase, for example, to completely close an air flap arranged in the inlet opening 21. But this is also discharged through the opening 36 virtually no moist, warm air 37 to the environment. The control of the mentioned air damper may for example be coupled to a thermostat arranged in the apparatus part, which determines the temperature of the drying air 33 heated after the condenser or of the air 39 introduced into the drying space. If the temperature, for example, of the air 39 introduced into the drying space exceeds a value of approx. 40-45 ° C., then an increased amount of air 19 is to be supplied through the opening 21 to the air circulation. To return to the above-mentioned example, it has been found in practice that it makes sense, for example, to supply to the total amount of air flow within the apparatus part 3 from the outside about 100 - 200 m ³ air, so that by the fan 35 in total about 1000 - 1100 m ³ drying air 39 is blown into the dryer room 1.

But it is also possible to make the bypass air quantity 18 and 32 variable, for example, in turn coupled with the arranged in the apparatus part thermostat. The greater the proportion of the bypass air quantity is chosen, the greater is due to the lower air resistance in the apparatus part 3, the amount of air conveyed by the fan 35. This results in an increase in the air flow rate in the dryer room 1, which as mentioned above is positive for the efficiency of the drying process.

According to a further embodiment of the invention, it is also possible, especially in combined operation of a dryer cabinet and a washing unit, such as a washing machine, in the heat pump or in the cooling unit Dissipate excess heat generated by power consumption by means of externally supplied cooling water through a cooling circuit or a heat exchanger, which, for example, the water required in the washing machine can be preheated. This additional cooling can be done via an additional circuit by this additional circuit preheated in a heat exchanger such as a boiler washing water to dissipate the heat generated in the heat pump. Of course, the heat dissipated so can be used for other purposes than for the heating of wash water.

The example of an embodiment of the present invention shown in FIGS. 1-4 is of course not limiting and may be modified, modified or supplemented by further elements in accordance with the content of the claims. In particular, the illustration of the discharge of the condensate has been omitted, for example in Figures 2 and 3, and neither a hygrostat nor a thermostat are shown, since their use in drying equipment, such as the drying cabinet described in the invention, is well known. For example, it is also possible to attach the apparatus part or the cooling unit laterally to the drying cabinet or below the drying cabinet or at the back of the cabinet.

Furthermore, the inventively proposed dryer cabinet is not limited for the drying of textiles used, but can of course be used for the drying of x-arbitrary parts to be dried, materials, equipment parts, equipment, tools, bulk material and the like.

Claims (15)

1. Drying chamber with a drying room (1) and an apparatus part (3) with one heat pump, consisting of an evaporator unit (15), a compressor (27) as well as a condenser (25) as well as with an air-circulation generating element (35) for generating an air-circulation within the chamber, with an air supply (21) from outside arranged within the apparatus part (3) between evaporator (15) and condenser (25), as well as an opening (36) to blow out (37) of the supplied airflow at the exit of the humid and warm discharged air (11) out of the drying room (1) to discharge excessive heat, whereas part (16) of the humid and warm discharged air (11) as circulating air is guidable through the heat pump, characterized in that within the apparatus part (3) at least an additional air channel is provided through which at least a further part (18) of the humid and warm discharged air (11) out of the drying room (1) is guidable at least almost unresistable through the apparatus part (3) as bypass air stream (18,32) to be guided at least almost untreated again into the drying room (1).
2. Drying chamber according claim 1, characterized in that the air channel is shaped at least into two parts, where a first part of the channel is arranged in the area and along the evaporation unit (15) and a second part in the area and along of the condenser (25).
3. Drying chamber according to one of the claims 1 or 2, characterized in that prearranged to the evaporator (15) a heat recovery unit (14) is arranged for precooling or prehumidifying respectively at least part of the warm and humid air, in which in cross- or counterflow the humid and warm air, leaving the drying chamber and the air, cooled and dehumidified by the evaporator (15) are guided.
4. Drying chamber according to one of the claims 1-3, characterized in that prearranged to the evaporator (15) a so-called plate heat exchanger (14) is arranged.
5. Drying chamber, according to one of the claims 1-4, characterized in that a cooling circuit is provided for the discharge of the excessive heat created due to power consumption of the heat pump.
6. Drying chamber according claim 5, characterized in that instead of a cooling circuit, a heat exchanger is provided for the heating of water, as e.g. washing water needed in a washing unit.
7. Process for the operation of a drying chamber as described within one of the claims 1-6, with a drying room (1) and an apparatus part (3) with a heat pump, consisting of a evaporation unit (15), a compressor (27) as well as a condenser (25) as well as with an air circulation generating element (35) for the generation of an air circulation within the chamber with an air supply (21) from outside arranged in the apparatus part (3) between the evaporator (15) and the condenser (25) as well as an opening (36) for discharging (37) of the supplied air flow at the exit of the humid and warm discharge air (11) out of the drying room (1) whereas part of (16) of the humid and warm discharge air (11) is guided through the heat pump as circulating air and whereas additional air is fed from outside to the circulating air between the evaporator (15) and the condenser (25), which additional air flow is again discharged at the exit of the drying room (1) as humid and warm discharge air (27) via the exit opening (36) to discharge excessive heat, characterized in that at least a part (18) of the humid and warm discharged air (11) leaving the drying room (1) is guided as so called bypass air stream (18,32) to be again fed into the drying room (1) at least almost untreated.
8. Process according claim 7, characterized in that at first a first bypass air stream (18) is guided within the apparatus part (3) in the area and along adjacent to the evaporator unit (15) and is mixed with the air quantity, dried and cooled within the evaporator unit whereupon the thus created air mixture (27) is eventually mixed and again divided with from outside of the drying chamber fed additional air (19) whereas at least a part of this air quantity again as so called second bypass air stream (32) is guided in the area or along the condenser (25) respectively to be subsequently again brought together with the air quantity (33) heated within the condenser (25) to be forced finally into the drying room (1) by means of the ventilator (35).
9. Process according to one of the claims 7 or 8, characterized in that the so called bypass air stream (18,32) is being kept almost constant during the operation of the drying chamber.
10. Process according to one of the claims 7 or 8, characterized in that the so called bypass air quantity is variably adjustable during the operation of the drying chamber.
11. Process according to one of the claims 7 to 10, characterized in that the bypass air quantity is controllable, and is coupled with a thermostat which adjustably varies the air quantity due to the temperature of the dry air.
12. Process according to one of the claims 7 to 11, characterized in that a part of the humid and wet discharged air (11) leaving the drying room (1) is guided through a heat recovery unit as for instance a plate heat exchanger (14) which is prearranged to the evaporator (15) to be conducted or cooled in counterflow or cross-stream to the air (16), dried and cooled by means of the evaporator (15).
13. Process according to one of the claims 7 to 12, characterized in that warming up of the heat pump created due to the power consumption is discharged at least partially by means of a cooling circuit, which heat can be used e.g. for the heating of rooms or for pre-heating of washing water for a washing unit.
14. Process according to one of the claims 7 to 13, characterized in that the bypass air quantity (18,32) is in the amount of between 10-40%, preferably 20-30% in relation to the total consumption of the circulating drying air.
15. Use of a drying chamber according to one of the claims 1-6, or a process according to one of the claims 7-14 respectively for drying of textiles or textile-similar materials, fabrics or fabric-containing materials respectively.

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