EP3575473B1 - Method for the wet treatment of laundry items assembled into laundry loads - Google Patents

Description

The invention relates to a method for the wet treatment of items of laundry combined to form laundry items according to the preamble of claim 1.

For the wet treatment of laundry, in particular dirty laundry, or laundry items in commercial washing machines, these are combined into laundry items. These batches of laundry are then wet-treated in the washing machine in several steps. Depending on the type of washing machine, the treatment takes place in several successive treatment zones of a drum that can be driven in rotation, for example in a conveyor-type washing machine, or in a chamber or drum of a washer-extractor that forms a single zone.

During the wet treatment of the laundry items, the laundry batches are treated gradually. In the case of a conveyor-type washing machine, the batch of laundry can pass through a prewash zone, a main wash zone and, if necessary, a rinse zone. In addition, it is conceivable that the batch of laundry also pass through a post-treatment zone. These different zones represent separate treatment areas, even if the entirety of the zones is formed by a drum. For the wet treatment of the laundry items, these are added successively to the pre-wash zone or an inlet of the drum and then pass through the individual wash zones until they are ejected from the same again at the end of the drum. In a washer extractor, the individual treatment steps take place in one and the same zone without the laundry items having to be moved to other chambers or zones.

From the DE 28 18 286 A1 a method and an arrangement for monitoring the operational sequence of a household washing machine are known. In this case, the water inlet and the pumping out of the washing liquid, the heating process and the running up of the engine are monitored. The monitoring is carried out for the purpose of the correct and safe functioning of control loops and control chains of the household washing machine.

From the DE 28 10 935 A1 a control arrangement for a washing machine with a drum receiving a single batch of laundry is known. Various functions of the selected washing program, movement devices and the temperature of the washing liquid are to be controlled. The control should be versatile and adaptable.

The WO 2012/026821 A1 discloses a conveyor washing machine for the industrial washing of textiles. This has an elongated drum in which chambers are arranged one behind the other, in each of which a batch of laundry can be treated. This makes it possible for this known conveyor-type washing machine to wash different items of laundry. The different batches of laundry are simultaneously subjected to different washing steps. At least one process parameter should be determined during at least the last two washing steps.

The invention is based on the object of creating a method for the wet treatment of items of laundry combined into laundry items, with which a reliable quality control of the wet treatment is possible.

A method for solving this problem has the measures of claim 1. Accordingly, it is provided to determine values for the temperature of the treatment liquid, the duration of each treatment step and movements of the drum and to compare these values with a corresponding predetermined reference value, specifically for each individual treatment step and for each individual item of laundry. By determining the values in this way and then comparing them with a reference, the wet treatment of the laundry items can be monitored in a very comprehensive and reliable manner. Through this extensive monitoring, on the one hand, the washing result is reproducible and, on the other hand, a high quality of treatment can be achieved. Such monitoring of the essential washing parameters is particularly advantageous for quality assurance but also for the documentation of the method.

A further advantageous embodiment of the present invention can provide that when the temperature of the treatment liquid and the duration of the treatment step and
the movement sequences of the drum and the concentration of the treatment additive with the reference values of these laundry items, for which the match was determined, is released for a next treatment step and that if at least one value deviates from the corresponding reference value, the laundry item is not released for the next treatment step. If, accordingly, a match is established for all of the parameters mentioned, the laundry item is given a corresponding “marking”. This "marking" can be either analog, digital or virtual. In the case of a virtual marking, a corresponding “OK” is assigned to this item of laundry in the control device. The control unit connects this "OK" with the batch of laundry for the rest of the wet treatment or for documentation and quality control. A digital marking could take place in such a way that corresponding transponders or storage media are written on the items of laundry or in the items of laundry with the corresponding "OK signal". If at least one parameter does not match the reference value, the corresponding item of laundry is also given a corresponding marking, which can possibly lead to a repetition of the treatment step or to the item of laundry being discharged from the process. The correspondence between the reference value and the determined values can take place within a tolerance range. For example, deviations of the determined values of up to 5% or up to 10% from the reference value are conceivable in order to still be assessed as a match.

In particular, an advantageous development of the invention consists in determining the concentration of at least one treatment additive in the treatment liquid and also comparing it with a corresponding reference value. This determination and the data comparison are also carried out for each individual item of laundry for each treatment step. Up to now, the titration in particular represented an uncertainty factor, since the concentration of the treatment additives was only determined randomly and sporadically. With this continuous documentation of the concentration for each batch of laundry, namely after each treatment step, an increased quality of the washing result can be achieved. This is particularly advantageous for items of laundry that must meet clinical requirements.

Provision can preferably also be made that the results of the comparison of the determined values with the reference values for each item of laundry and for each Treatment step can be displayed visually. For this purpose, a display device, such as a lamp or a screen, can be provided directly on the washing machine, on which the determined actual values are compared with the setpoint values, numerically or in color. This representation can be shown separately for each treatment step and / or each batch of laundry. For example, a separate diagram is shown for each zone or for each chamber and / or for each laundry item for continuous washing machines having several treatment zones, in which the actual value is shown or compared with the target value or the reference value. This visual representation allows the treatment result to be seen at a glance. A person operating the washing machine can quickly and reliably see whether the actual values agree with the reference values or not. The method can be given a high level of reliability and simple evaluation, in particular by means of colored marking.

In addition, it can be provided that the result of the comparison is stored for each individual item of laundry for documentation purposes, in particular on a storage medium assigned to the item of laundry. This documentation allows a statement to be made about the quality of the treatment even after the end of the wet treatment. This information is particularly important for quality assurance. The stored data can be used to determine why the desired washing result was not achieved. On the basis of these results, for example, the parameters can be changed so that the desired correspondence of all four parameters with the reference values is achieved.

Preferably, it can be provided that to determine the concentration of the at least one treatment additive in the treatment liquid during the treatment of the laundry items, a partial amount of the treatment liquid is removed from the drum, preferably from an outer drum, and a corresponding measurement, in particular a titration, of the treatment liquid is made or the measurement is made inside the drum. This measurement of the concentration during the treatment process means that the wet treatment does not have to be interrupted become. On the one hand, this saves time and, on the other hand, the measurement is carried out precisely on the liquid in which the laundry items are treated. This enables a particularly high level of accuracy and thus reliability to be achieved.

Another exemplary embodiment can provide that the temperature of the treatment liquid inside or outside the drum is determined for each treatment step and for each item of laundry by a temperature measuring sensor. The temperature measuring sensors can, for example, be temperature sensors inside the drum or measuring sensors that are positioned outside the drum and measure the temperature via infrared sensors.

It can further be provided that a change in the direction of rotation of the drum or a number of pivoting movements of the drum is measured in order to determine the movement sequences of the drum. Depending on the design, the drums can perform different sequences of movements during treatment. For drums that are only swiveled back and forth in relation to the longitudinal axis or the central axis, the number of swivel movements is measured. For drums that make complete rotations, the number of rotations is counted to determine the motion sequences. The number of rotations or pivoting movements can be measured from the outside in a simple and very reliable manner. Since the movement of the drum is transferred directly to the movement of the items of laundry, this is a particularly good measure for determining the mechanical load on the items of laundry.

In particular, it can be provided according to the invention that the duration of the treatment step is determined and / or determined by changing the direction of rotation of the drum or by a specific number of pivoting movements of the drum. A change in a treatment step is usually initiated by changing the direction of rotation or by ending the pivoting movements. Therefore, the mentioned movement sequences are good markers for determining the duration of the treatment step.

A further exemplary embodiment can provide that a batch of laundry is guided through the successive treatment steps until a correspondence with the references is established for all determined values. A batch of laundry that is output from the washing machine and has not received approval for further treatment steps or delivery is included in the washing process or fed back into the washing machine. If necessary, the parameters that did not lead to a match with the reference values must be changed.

Preferred exemplary embodiments of the method are explained below with reference to the drawing. The single figure of the drawing shows a schematic side view of a commercial washing machine designed as a conveyor-type washing machine.

The process described here for the wet treatment of items of laundry grouped into laundry batches will be carried out in a commercial washing machine. This commercial washing machine is a conveyor-type washing machine. The method according to the invention is explained in more detail below.

The figure shows a conveyor-type washing machine 10 and a dewatering device designed as a dewatering press 11. The dewatering press 11 is arranged behind the conveyor washing machine 10 as seen in the direction 12 of the laundry items passing through the conveyor washing machine 10. A laundry centrifuge can also be arranged in place of the dewatering press 11.

The conveyor-type washing machine 11 has an elongated drum 13 in which a plurality of identical or different chambers 14 are provided. In the drum 13 of the conveyor-type washing machine 10 shown, thirteen chambers 14 are provided in succession in the direction of flow 12. However, the invention is not restricted to this. The invention is also suitable for conveyor washing machines 10 with a smaller or larger number of successive chambers 14.

The elongated drum 13 can be driven to rotate about a central axis of rotation which lies on a central longitudinal axis 15 of the conveyor-type washing machine 10. This rotating drive can be done in various ways. For example, the drum 13 can be driven to rotate, but also only rocking or pivoting. Then the drum 13 is not driven to rotate with complete revolutions. A combination of a rotating or pivoting or rocking drive of the drum is also conceivable.

Several successive treatment zones are formed in the conveyor-type washing machine 10, namely a prewash zone, a subsequent main wash zone and, if necessary, a rinsing zone and / or an aftertreatment zone, as seen in the flow direction 12, for example. An inlet funnel 16 of the conveyor-type washing machine 10 opens into the first chamber 14 of the prewash zone. The laundry items of the individual items are loaded into the first chamber 14 of the conveyor-type washing machine 10 via this. This first chamber 14 is also the first chamber of the prewash zone. Behind the last chamber 14 of the conveyor-type washing machine 10, seen in the flow direction 12, there is an unloading chute 17, via which items of laundry that have been wet-treated in the conveyor-type washing machine 10, namely at least washed, but possibly also rinsed and / or post-treated items of laundry, enter the dewatering press 11 or some other dewatering device. In the dewatering press, at least one dewatering of the washed laundry takes place in such a way that part of the bound liquor from the conveyor-type washing machine 10 is separated from the laundry. The dewatering press 11 can, however, also serve to rinse the laundry coming from the conveyor washing machine 10. The conveyor-type washing machine 10 then has no rinsing zone.

In the conveyor washing machine 10, the items of laundry are batchwise, i. H. in batches of laundry, washed. For this purpose, a batch of laundry with a larger number of items of laundry is located in each chamber 14 of the conveyor-type washing machine 10 or, if necessary, only in some chambers 14.

The laundry items are treated with treatment liquid in a bath in the conveyor washing machine 10, in particular washed or optionally rinsed and / or equipped. At least one treatment additive is added to the items of laundry and the treatment liquid. These can be detergent substances, disinfectants and / or bleaches, but also other washing aids. At least one treatment additive is added to the treatment liquid with the laundry located therein in the first chamber 14 of the prewash zone, that is to say the first chamber 14 of the conveyor-type washing machine 10.

Alternatively or additionally, at least one treatment additive can also be added to at least one other chamber of the conveyor-type washing machine 10. This can be, for example, the main wash zone, preferably the first chamber 14 of the same, the rinsing zone, if the conveyor-type washing machine 10 has one, and / or one be in the conveyor washing machine 10 existing post-treatment zone. Different treatment additives can be added to the laundry items in the individual zones, for example detergents in the prewash zone, neutralizing agents and / or disinfectants in another zone and bleaching agents and / or finishing agents in yet another zone.

The conveyor washing machine 10 has suitable measuring instruments for measuring the amount, the content and / or the concentration of the at least one treatment additive in the laundry and the treatment liquid. Corresponding measurement sensors are assigned to that chamber 14 or those chambers 14 of the conveyor-type washing machine 10 in which the treatment liquid and / or the laundry is to be measured with regard to their content or the concentration of the at least one treatment additive.

It is also conceivable to assign a sampling line with at least one filter, if necessary, to the relevant chamber 14 of the conveyor-type washing machine 10 and to assign the measured value recorders to the relevant sampling line.

The concentration or the content of the at least one treatment additive in the treatment liquid detected by the at least one transducer is transmitted to an evaluation unit, not shown in the figure, which evaluates the measured values obtained or compares them with a reference value. If necessary, if the measured value deviates from the reference value, subsequent dosing of the treatment additive can be controlled or regulated.

In addition, temperature measuring sensors are assigned to at least one, preferably several chambers 14 of the various treatment zones. The temperature of the treatment liquid can be measured via these temperature measuring sensors. The measured values determined for the temperature are also transmitted to an evaluation unit or to a control unit, where they are compared with a setpoint value for the temperature. Here, too, if the measured value deviates from the reference, the temperature can be controlled or regulated.

In order to determine the whereabouts of the individual laundry items in the individual chambers 14 or in the individual washing zones, either the transition of the individual laundry items from one chamber to the next or from one washing zone to the next can be used as the start and the exit from the chamber 14 or zone as a stop be used. Alternatively, a change of direction in the movement sequence of the drum 13 can also be used as a stop or start signal for the time measurement. A number of several successive pivoting movements of the drum 13 are also suitable for determining the dwell time of individual items in the chambers 14 or washing zones. The measured values determined for the duration of the individual items of laundry in the chambers 14 or the time interval that lasts a treatment step are also transmitted to an evaluation unit and compared with corresponding reference values. If the measured value deviates from the reference value, the treatment can possibly be extended or shortened.

In order to determine the mechanical load on the individual items of laundry, the number of pivoting movements of the drum 13 or the completed rotational movements of the drum 13 is measured. These measured values are also forwarded to an evaluation unit or control unit and compared with a reference value.

The method according to the invention runs as follows with the conveyor-type washing machine 10 described above: The items of laundry combined into batches of laundry are washed batch-wise in the conveyor-type washing machine 10. A batch of laundry is preferably located in each chamber 14. If necessary, individual chambers 14 between successive items of laundry cannot be loaded with any items of laundry, for example at least one empty compartment 14 can be provided between items of laundry with laundry of different types.

The items of laundry are treated with treatment liquid in the chambers 14 at a predetermined temperature. To do this, the heating elements are set accordingly for each chamber. In addition, at least one treatment additive is added to the treatment liquid in at least one treatment zone of the conveyor-type washing machine 10. In all or some of the treatment zones, different treatment additives can be added to the treatment liquid with the laundry contained therein. The treatment of the laundry items of the individual items takes place in each chamber or in each zone for a predetermined duration. This means that each treatment step is limited in time. For a sufficient treatment result, the drum is swiveled several times or rotated completely for the wet treatment. All four parameters, namely the temperature, the duration, the concentration of the treatment additive and the movement sequence of the drum 13 are determined individually for each item of laundry and for each drum 13. This quartet out Treatment parameters are transmitted to the system control or an evaluation unit and compared with the corresponding references. Both the measured values and the reference values are displayed visually. This can be done, for example, on a single display, so that an operator can see at a glance which parameters are or are not fulfilled for which item and for which chamber 14. However, it is also conceivable that each chamber 14 is assigned a corresponding display for the visual representation of the measured parameters and the corresponding references.

If it was possible to determine measured values for a batch of laundry which correspond to the references at least in a predetermined tolerance range, an “OK signal” is output by the evaluation unit, with which the corresponding batch of laundry is marked. This information is saved and saved for documentation or quality assurance of the treatment result. If at least one of the measured parameters does not match a reference, no "OK signal" is generated for this item of laundry. In other words, this batch of laundry does not meet the quality requirements and is not further treated or delivered. This batch of laundry can either be sorted out or fed back for treatment in that it is placed in the inlet funnel 16.

By determining the four parameters mentioned for each item and for each chamber 14, a very precise check of the wet treatment can be achieved. The determination of the individual parameters can take place cyclically or periodically or continuously during the treatment of the laundry items in a chamber 14. In particular, the measurement of the temperature and the concentration of the treatment additive can, however, also take place at the beginning or at the end of a treatment step.

Alternatively, the method according to the invention can also be carried out in a washer extractor, not shown here (not part of the claimed subject matter). In contrast to a conveyor-type washing machine, the washer-extractor has an inner drum that can be driven in rotation and has a pivotable axis of rotation. This inner drum has only a single, essentially full-area opening on one end face. The inner drum is both loaded and unloaded through this opening with the individual laundry items of a laundry batch. In addition, the washer-extractor has a watertight drum housing that surrounds the water-permeable inner drum and that is fixed relative to the inner drum is. In contrast to the inner drum, the drum housing cannot be driven to rotate. The drum housing also has a single, almost full-surface opening on one end face. The opening of the drum housing is located in that end face of the drum housing to which the opening of the inner drum also points, so that the openings are adjacent to one another and thus correspond to one another.

The method described above using the example of the conveyor-type washing machine 10 can be transferred directly to the wet treatment of the laundry items in the inner drum of the washer-extractor. Here, too, the four aforementioned parameters for wet treatment are determined and compared with the corresponding specified reference values. Both the determined measured values or parameters and the corresponding reference values are displayed visually on the washer extractor, so that an operator can see the status of the treatment at a glance at any time. In addition, the individual items of laundry are marked exactly as described above, depending on the comparison of the measured values with the reference values. In the washer extractor, not shown here, too, the batches of laundry go through several consecutive treatment steps. For each of these treatment steps, the comparison of the data carried out is documented or logged and displayed. As a result, the method according to the invention can also be displayed visually in a washer extractor and documented for quality control.

List of reference symbols:

10

Conveyor washing machine

11

Dewatering press

12th

Flow direction

13th

drum

14th

chamber

15th

Longitudinal central axis

16

Inlet funnel

17th

Discharge chute

Claims (12)

1. Method for the wet treatment of items of laundry, combined to form a batch of laundry, in a continuous washing machine (10) having separate treatment zones, wherein the wet treatment of the batches of laundry is performed in a rotationally driveable drum (13) of the washing machine in successive treatment steps in the separate treatment zones in a treatment liquid, characterized in that, for each treatment step and for each batch of laundry, the temperature of the treatment liquid, the duration of the treatment step and movement sequences of the drum (17) are determined and compared in each case with a reference value and, if the temperature of the treatment liquid, the duration of the treatment step and the movement sequences of the drum (17) agree with the reference values, said batch of laundry for which the agreement has been established is released for a next treatment step and, if at least one value deviates from the corresponding reference value, the batch of laundry is not released for the next treatment step.
2. Method according to Claim 1, characterized in that, for each treatment step and for each batch of laundry, a concentration of at least one treatment additive in the treatment liquid is determined and compared in each case with a reference value.
3. Method according to Claim 2, characterized in that, if the temperature of the treatment liquid, the duration of the treatment step, the movement sequences, in particular a number of oscillations or rotations, and the concentration of the treatment additive agree with the reference values, the corresponding batch of laundry for which the agreement has been established is released for a next treatment step, and in that, if at least one value deviates from the corresponding reference value, the batch of laundry is not released for the next treatment step.
4. Method according to Claim 1 or 2, characterized in that there is a visual display of the results of the comparison of the values determined with the reference values for each batch of laundry and for each treatment step.
5. Method according to one of the preceding claims, characterized in that each individual batch of laundry is marked in a manner corresponding to the result of the comparison, wherein the marking takes place in analogue, digital or virtual fashion.
6. Method according to one of preceding Claims 1 to 4, characterized in that the result of the comparison for each individual batch of laundry is stored for documentation purposes, in particular on a storage medium assigned to the batch of laundry.
7. Method according to one of the preceding claims, characterized in that, for the purpose of determining the concentration of the at least one treatment additive in the treatment liquid during the treatment of the items of laundry, a sub-quantity of the treatment liquid is discharged from the drum (17), preferably from an outer drum, and a corresponding measurement, in particular a titration, is performed on the treatment liquid, or the measurement for the purpose of determining the concentration of the at least one treatment additive in the treatment liquid takes place within the drum (17) .
8. Method according to one of the preceding claims, characterized in that a temperature-measuring sensor is used to determine the temperature of the treatment liquid within or outside the drum (17) for each treatment step and for each batch of laundry.
9. Method according to one of the preceding claims, characterized in that, for the purpose of determining the movement sequences of the drum (17), a change in the direction in which the drum (17) revolves or a number of pivoting movements of the drum (17) is measured.
10. Method according to one of the preceding claims, characterized in that the duration of the treatment step is defined and/or established by a change in the direction in which the drum (17) revolves or by a certain number of pivoting movements of the drum (17) .
11. Method according to one of the preceding claims, characterized in that a batch of laundry is guided through the successive treatment steps until, for all values determined, agreement with the references is established.
12. Method according to one of the preceding claims, characterized in that the treatment steps take place in such separate treatment zones of the continuous washing machine (10) as a pre-wash zone, a final-rinse zone and/or a rinse zone and/or an aftertreatment zone.

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