EP2707533B1 - Method for sterilizing laundry, and washing-drying unit - Google Patents

Description

The invention relates to a method for sterilizing temperature-sensitive laundry items with the following features: the laundry items are dry-exposed and heated for a predetermined period of time in the absence of water to a process air stream of defined temperature, and then the thus heated items of laundry are heated to a defined temperature significantly reduced setpoint temperature cooled. Moreover, the invention relates to a washer-dryer unit.

Such a method and a drying and sterilization cabinet for its implementation are the EP 0 262 451 A2 removable. According to this document, pieces of laundry are sterilized immediately after being dried.

The US 2007/0169282 A1 and the JP 4-158896 A respectively relate to a method and a washing machine for carrying it out, in which method items to be washed are first steamed to sterilize and moisten them or to dissolve their fibers and then to be washed only with the addition of wash water.

Sensitive laundry is known to be washed only at low temperature (eg, room temperature or 30 ° C to 40 ° C) because at higher wash temperatures, the fabric or dyeing of the laundry would suffer and be damaged, at least over many washes. This can lead to the decolorization of a textile or the transfer of color from one to another textile. Disadvantage of washing at low temperature, however, is that in the laundry contained germs are not killed by such washing to the extent as when washing at high temperature such. B. 95 ° C (so-called cooking linen). This disadvantage has been partially circumvented by the fact that the still wet laundry is exposed to the washing process by means of a tumble dryer hot air.

Such a possibility also reveals the DE 10 2005 052 960 A1 , However, sensitive laundry also suffers here, since it is still exposed to the hot air at least in the initial phase in a moist state and this sensitivity is primarily in the wet state. In addition, relatively much energy is needed for such heating, since not only the textile itself, but also the water contained in the textile heated, possibly also evaporated, must be. The possibility indicated in the cited document that the laundry can be supplied to a hot air treatment for disinfecting only after completion of the drying process, can not be realized in practice, as they only in a cabinet-like structure of a washing and drying unit with a common treatment room for washing with subsequent drying and sterilization in which the laundry is placed hanging, would have to be feasible. However, as the past has already shown, such a structure does not prevail on the market for washing and drying appliances. Thus, this idea is not feasible in practice.

The DE 33 43 236 A1 discloses a drying cabinet, in which the laundry still wet from a previous washing process is introduced, where it is first dried and then sterilized thereon.

It is an object of the invention to provide a method by means of which delicate laundry can be better sterilized with the greatest possible protection of the material than with traditional washing / drying processes. It is a further object of the invention to provide a washing drying unit, by means of which the inventive method is feasible.

This object is achieved according to the features of the independent claims. Preferred embodiments can be taken from the dependent claims and the following description, wherein preferred embodiments of the process correspond to preferred embodiments of the washer-dryer unit and vice versa, even if not explicitly stated herein.

• die Wäschestücke werden in trockenem Zustand über einen vorgegebenen Zeitraum (T) hinweg in Abwesenheit von Wasser einem Prozessluftstrom von definierter Temperatur (Tp) ausgesetzt und erhitzt,
• anschließend werden die so erhitzten Wäschestücke auf eine gegenüber der Temperatur (Tp) deutlich reduzierte Solltemperatur (Tpsoll) abgekühlt, und
• daran anschließend (erst) gewaschen.

The method according to the invention for sterilizing temperature-sensitive laundry items accordingly has the following features:

• the laundry items are exposed to a process air flow of defined temperature (Tp) in the dry state over a predetermined period (T) in the absence of water and heated,
• Subsequently, the thus heated items of laundry are cooled to a relation to the temperature (Tp) significantly reduced target temperature (Tpsoll), and
• then washed (first).

The method according to the invention has the advantage that the hot air supplied to the laundry in the first process step damages the delicate laundry far less than during a drying process subsequent to a washing process. Due to the absence of water and a removal of color from a textile treated according to the invention and thus both discoloration and transfer to another textile is excluded. Also, a shrinkage of the laundry is prevented by the action of water at elevated temperature. Yet another advantage lies in the fact that for sterilizing less energy for heating the (still) dry Laundry is required as with a corresponding heating conventional wet laundry.

A preferred embodiment of the invention provides that the setpoint temperature (Tp _soll ) corresponds to a room temperature (Tp _space ), ie the temperature of an environment of the device or device in which the method is carried out. It is therefore in particular the temperature of about 20 ° C usually prevailing in an inhabited closed room.

A first particularly preferred, further developed embodiment of the invention provides that the setpoint temperature (Tp _soll ) is equal to a maximum washing temperature that occurs during the washing process. This ensures that the maximum permissible temperature is never exceeded during the subsequent washing of the laundry items. A second particularly preferred, further developed embodiment of the invention provides that the target temperature (Tp _soll ) is calculated using a previously determined loading amount of laundry items which are sterilized and a predetermined washing temperature of the subsequent washing program, so that after the addition of water to the amount of laundry sets a temperature in the laundry sets, which is less than or equal to the washing temperature. In this way, the heat used for sterilization is advantageously utilized in the subsequent washing process. More preferably, the laundry items are dried after washing in a conventional manner, which then also creates a connection to a conventional drying process.

Another preferred embodiment of the invention provides that a period of between five and twenty-five minutes is selected as the predetermined period (T), in particular one between ten and twenty minutes, inclusive.

A further preferred embodiment of the invention provides that a temperature with a value range between 60 ° C and 120 ° C is specified as the defined temperature (Tp), in particular one between 70 ° C and 90 ° C, inclusive.

Yet another preferred embodiment of the invention provides that a temperature of the process air flow is measured immediately before the laundry is exposed to it, and a temperature of the process air flow is measured immediately after the laundry has been exposed to it and both measured temperatures to control the temperature the laundry items are used.

The washer-dry unit according to the invention accordingly has a control device for carrying out the method according to the invention or one of its preferred developments.

• sie setzt die trockenen Wäschestücke über einen vorgegebenen Zeitraum hinweg in Abwesenheit von Wasser einem Prozessluftstrom von definierter Temperatur zu deren Erhitzen aus,
• anschließend kühlt sie die so erhitzten Wäschestücke auf eine gegenüber der definierten Temperatur deutlich reduzierte Solltemperatur ab, und
• daran anschließend startet sie ein zuvor ausgewähltes Waschprogramm der Waschtrockeneinheit.

Accordingly, the washer-drying unit according to the invention has a control device for carrying out a method for sterilizing temperature-sensitive laundry items in the washer-dryer unit. The control device has the following functions:

• it exposes the dry laundry items for a predetermined period of time in the absence of water to a process air stream of defined temperature for heating them,
• Subsequently, it cools the thus heated items of laundry to a relative to the defined temperature significantly reduced target temperature from, and
• Thereafter, it starts a previously selected wash program of the washer-dryer unit.

A preferred embodiment of the invention provides that in the washer-drying unit, a timer unit is provided, by means of which the predetermined period (T) is predetermined by value.

Another preferred embodiment of the invention provides that a temperature control unit is provided in the washer-drying unit, by means of which the desired temperature (Tp _soll ) can be predetermined in terms of value and, in particular, as described above, can be calculated. Still preferably, the temperature control unit includes a first temperature sensor for measuring a temperature of the process airflow immediately after the laundry items have been exposed to it, and a second temperature sensor for measuring a temperature of the process airflow immediately before the laundry items are exposed to it, and is the temperature control unit arranged such that both measured temperatures are used to control the temperature of the laundry items.

A further preferred embodiment of the invention provides that in the washer-dryer unit, the control device is designed so that it starts a previously selected wash program of the washer-dryer after completion of the cooling down.

Hereinafter, a preferred embodiment of the invention will be explained in more detail with reference to the drawing.

Fig. 1

Temperaturverläufe beim Ausüben des Verfahrens;

Fig. 2

die Waschtrockeneinheit in symbolischer Darstellung; und

Fig. 3

einen vertikalen Schnitt durch die Waschtrockeneinheit.

In the drawing show:

Fig. 1

Temperature profiles when practicing the process;

Fig. 2

the washing dry unit in symbolic representation; and

Fig. 3

a vertical section through the washer-dryer unit.

In the process, the laundry to be washed, ie the laundry items to be washed, is heated in a still dry state (ie, even before the start of the actual washing process) by means of a process air flow. The heating takes place at a defined temperature Tp, which is either fixed by the heating device or can be preselected. It is advantageous if the defined temperature Tp is selected in a value range between 60 ° C and 120 ° C, in particular in a value range between 70 ° C and 90 ° C, each inclusive. After reaching the defined temperature Tp, the laundry is exposed to this temperature for a given period T, the given period T being between five and twenty five minutes, in particular between ten and twenty minutes, inclusive. The given period T is fixed either by the device causing the heating or it is preselected. The heating in the hot air flow causes the intended sterilization, namely an almost complete killing of the germs contained in the laundry such. As bacteria, viruses, mites etc.

Following this heating, the laundry is cooled. After cooling, the laundry is washed in a further development of the invention in a conventional manner and also dried. The drying can be carried out, for example, in a dryer at low, the sensitivity of the laundry adapted temperature, since the sterilization of the laundry has already taken place. The laundry is characterized much more spared than when drying at a correspondingly high temperature in the context of a conventional washing-drying process, since the laundry is heated only in the dry state above the maximum temperature permissible for washing. Another advantage of this development is that the germs killed in the previous treatment of the laundry with process air flow are flushed out of the laundry items by the subsequent washing process and thus removed therefrom. Namely, in the methods of the conventional washing-drying process without the preliminary sterilization, the germs are not killed until the drying process following washing, leaving their remains in the dried laundry.

The cooling down is carried out until the sterilized laundry, depending on the selected embodiment of the method according to the invention, room temperature Tp _room or a target temperature Tp _soll , the value is approximately equal to a washing process in the subsequent washing maximum washing temperature, or at the after the subsequent addition of water for washing in the laundry sets a temperature less than or equal to the washing temperature.

Fig. 1 shows the two possible gradients of the temperature Temp, shown over the time t. In one case, the temperature Temp rises from the room temperature Tp _space to the defined temperature Tp. There, it remains over the predetermined time period T, in order then to drop to the setpoint temperature Tp _soll . In the other case, the temperature profile is initially the same as described above in one case. After the end of the predetermined period T, however, the temperature Temp then drops to the room temperature Tp _space , which is shown partially in dashed lines.

To carry out the method, it is advantageous to carry out a combined washing-drying unit (in which washing and drying are carried out in one and the same drum, so that no transfer of the laundry from a washing machine to a tumble dryer It is necessary) to provide, according to the invention, a control device CTRL, which controls the usually existing components of a combined washer-dryer unit including pump (s) for water inlet and outlet, hot air device, motor (s) for moving the laundry drum and a program control unit so that in Operation overall, the inventive method is performed. Such a combined washer-dryer is symbolic in Fig. 2 shown. It is advantageous if the combined washer-dry unit has a timer unit Z, by means of which the defined period of time T can be predetermined in terms of value. Furthermore, it is also advantageous if the combined washer-dryer unit has a temperature control unit TS, by means of which the setpoint temperature Tp _{soll should be} predetermined in terms of value, to which the laundry items are to be cooled at the end of the sterilization process.

The control device CTRL is advantageously designed so that it starts after disinfecting and cooling down the laundry a previously directly or indirectly selected wash program. Indirect selection is understood to mean that a desired washing program is already selected with the selection "disinfecting".

FIG. 3 shows a vertical section through a washer-dryer unit. To see is laundry 1, which is located in a rotatable drum 2, which in turn is received in a swinging suspended, but not rotatable tub 3. The tub 3 is located with all other components of the washer-dryer unit in a housing 5. About a waterproof connected to the tub 3 and the housing 5, movable sleeve 6 is an access of created outside the housing 5 to the tub 3 and the drum 2; This access is closed by a door 7. An inlet 8 for fresh water and a drain 9 for wastewater, the latter also provided with a pump 10, are also present. The same applies to a flushing device for laundry treatment agent and arranged in the tub heater for heating the washing liquid, which are not shown here for the sake of clarity. A process air channel 11 with a fan 12 and a heater 13 are provided to drive process air, symbolized by arrows 14, through the drum 2 and the laundry 1 located therein. Not shown is a condenser, with which moisture which has extracted the heated by the heater 13 process air from the laundry, is condensed out of the process air, wherein the resulting liquid condensate flows into the tub 3 and is disposed of through the drain 9. Two temperature sensors 15 and 16 connected to the temperature control unit TS serve to control and regulate the temperature of the flowing process air 14. A first temperature sensor 15 is placed in the process air duct 11 so that it measures the temperature of the process air 14 flowing directly from the tub 3; the second temperature sensor 16 is placed in the process air duct 11 so that it measures the temperature of the process air 14 flowing from the heater 13. Thus, a very sensitive control of the temperature of the process air is possible, on the one hand heat the laundry items 1 quickly and on the other hand to keep the temperature of the laundry items 1 always in the desired and never excessive amount. In order to allow a rapid heating to a desired high temperature Tp, the process air 14 must have a slightly above the temperature Tp when entering the tub 3; To control this, the second temperature sensor 16 is used. With the first temperature sensor 15, the temperature of the laundry items 1 in the tub 1 can be estimated relatively accurately, so that exceeding the temperature Tp in the laundry items 12 can be safely avoided.

The process air duct 11 with blower 12, heater 13, first temperature sensor 15 and second temperature sensor 16 also serves to sterilize the laundry 1 as described in a dry state by hot process air is conveyed through the dry laundry 1 in the manner already described. This is controlled by the already mentioned control unit CTRL, which is connected to all the components just mentioned for their operation and application, in FIG. 3 however, for clarity's sake not shown. After sterilization, the laundry 1 can then be washed in a conventional manner.

The combined washer-dryer also has the advantage that at the beginning of the washing process in their components due to the previous Entkeimprozesses still stored residual heat can be used for heating the possibly necessary for the washing process reheating the wash water, which contributes to a total (further) energy savings.

LIST OF REFERENCE NUMBERS

t

Time

T

predetermined period

Temp

temperature

tp

defined temperature

Tp _should

set temperature

Tp _room

room temperature

CTRL

control device

Z

Timer unit

TS

Temperature Controller

1

laundry

2

drum

3

tub

4

engine

5

casing

6

cuff

7

door

8th

Intake

9

procedure

10

pump

11

Process air duct

12

fan

13

heater

14

process air

15

first temperature sensor

16

second temperature sensor

Claims (12)

1. Method for sterilising temperature-sensitive laundry items (1), having the following features:

   - the laundry items (1) are exposed, in the dry state, to a process air flow (14) over a specified time period (T) at a defined temperature (Tp) in the absence of water and heated,

   - thereafter, the laundry items (1) heated in this way are cooled to a target temperature (Tp_target) which is significantly reduced in comparison with the defined temperature (Tp), characterised in that

   - thereafter, the cooled laundry items (1) are washed in a washing process.
2. Method according to claim 1, the target temperature (Tp_target) corresponding to a room temperature (Tproom).
3. Method according to claim 1, the target temperature (Tp_target) being equal to a maximum washing temperature arising during the washing process.
4. Method according to claim 1, wherein the target temperature (Tp_target) is calculated using a previously determined load quantity of laundry items (1) which are to be sterilised and a previously specified washing temperature for the washing procedure, so that following the addition of water to the load quantity, a temperature becomes established in the laundry items (1) that is lower than or equal to the washing temperature.
5. Method according to one of the preceding claims, characterised in that the laundry items (1) are dried after washing.
6. Method according to one of the preceding claims, characterised in that, as the specified time period (T) a time period in the range of five minutes to twenty-five minutes is selected, in particular a time period in the range of ten minutes to twenty minutes, inclusive in each case.
7. Method according to one of the preceding claims, characterised in that as the defined temperature (Tp), a temperature is specified with a value in the range of 60°C to 120°C, in particular, in the range of 70°C to 90°C, inclusive in each case.
8. Method according to one of the preceding claims, characterised in that a temperature of the process air flow (14) is measured immediately before the laundry items (1) are exposed thereto and a temperature of the process air flow (14) is measured immediately after the laundry items (1) have been exposed thereto and both the measured temperatures are used to regulate the temperature of the laundry items (1).
9. Washing-drying unit, characterised in that said washing-drying unit has a control device (CTRL) for carrying out a method for sterilising temperature-sensitive laundry items in the washing-drying unit, wherein the control device (CTRL) comprises the following functions:

   - said control device exposes the dry laundry items (1) to a process air flow (14) over a specified time period (T) at a defined temperature (Tp) in the absence of water for the heating of said laundry items (1),

   - thereafter, the control device cools the laundry items (1) that have been heated in this way to a target temperature (Tptarget) which is significantly reduced in comparison with the defined temperature (Tp), characterised in that

   - thereafter, the control device starts a pre-selected washing program of the washing-drying unit.
10. Washing-drying unit according to claim 9, characterised in that said washing-drying unit has a timing unit (Z) by means of which the defined value of the time period (T) can be specified.
11. Washing-drying unit according to one of claims 9 and 10, characterised in that said washing-drying unit has a temperature control unit (TS) by means of which the value of the target temperature (Tp_target) can be specified.
12. Washing-drying unit according to claim 11, characterised in that the temperature control unit (TS) comprises a first temperature sensor (15) for measuring a temperature of the process air flow (14) immediately after the laundry items (1) have been exposed thereto, and a second temperature sensor (16) for measuring a temperature of the process air flow (14) immediately before the laundry items (1) are exposed thereto, and that the temperature control unit (TS) is configured such that both the measured temperatures are used to regulate the temperature of the laundry items (1).

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