EP3219842B1 - Method for wet treating of laundry - Google Patents

Description

The invention relates to a method for the wet treatment of laundry in commercial washing machines according to the preamble of claim 1.

In the wet treatment of laundry, treatment additives are used, in particular detergent substances, washing auxiliaries, disinfectants, bleaches, finishing agents or the like.

The at least one treatment additive is added to the laundry in a specific dosage, that is to say an amount that is dependent on the weight of the laundry, in particular the item of laundry to be treated, the type of laundry and / or the method of treatment. For reasons of cost, efforts are made to keep the amount of the at least one treatment additive to be metered as low as possible. It has been shown that this type of dosage of the at least one treatment additive often does not meet the requirements. For example, particularly heavy soiling of the laundry and some types of soiling lead to the at least one treatment additive being eliminated quickly and the wet treatment then not being able to be carried out to a sufficient extent. This is especially true for the disinfection of laundry. Particularly aggressive soiling of the laundry consumes large amounts of the disinfectant for a short time, so that complete disinfection of the laundry, in particular the laundry item in question, is no longer guaranteed, especially if a sufficient amount of disinfectant has not been added for reasons of cost.

In order to avoid the problems mentioned above, in practice the at least one treatment additive is metered in with excess. This makes wet treatment more expensive and also has a negative impact on the environment, because especially when it is usually soiled Laundry the treatment liquid to be disposed of still contains a not inconsiderable proportion of the added treatment additive.

From the DE 42 04 806 A1 a washing method for commercial laundries is known in which detergent or bleaching agents are replenished by comparing the actual concentration with a predetermined target concentration. In this known method, the detergent or bleaching agent is overdosed in that residues are rinsed out. As a result, detergents and bleaching agents are lost unused and the rinsing water is polluted by superfluous washing agents and bleaching agents.

From the DE 10 2007 011 119 A1 a household washing machine is known in which different detergents can be reliably identified by a color-sensitive sensor device. By measuring the intensity of the colors during the washing process, detergent consumption can be determined and a corresponding additional dosage can be made. The household washing machine known from this document cannot meet the requirements that are placed on commercial laundry machines.

From the DE 39 11 028 A1 , the DE 195 29 787 A1 and the US 2014/0259441 A1 Household washing machines are known in which the current content of detergents is determined and detergents are partly added in portions. These procedures involve overdosing the detergent. At least these known methods allow the detergent to be overdosed.

The invention is based on the object of creating a method for the wet treatment of laundry in commercial washing machines which is more economical with regard to the consumption of treatment additives and which ensures reliable disinfection.

A method for solving this problem has the measures of claim 1. In this method it is provided that initially only a minimum amount of the at least one treatment additive is added to the laundry. Preferably, only such an amount of at least one treatment additive is initially added to the laundry that is always required even in the case of lightly soiled laundry. A certain time after the addition of the at least one treatment additive, the current content of the same is measured at least once. The measurement result is then used to determine how high the content of the at least one treatment additive that has not yet been consumed at the time of the measurement is. Shortly after the addition of the minimum amount of the at least one treatment additive, it is preferably determined how much of it has been consumed or consumed in a certain time or period of time since the addition. This enables conclusions to be drawn about the degree of soiling of the laundry. Subsequently, if necessary, the at least one treatment additive is replenished. At the According to the method according to the invention, the at least one treatment additive is added in a targeted manner as required. The at least one treatment additive can thereby be metered in in a targeted manner, adapted to the degree of soiling of the laundry to be treated. In this way, sufficient quantities of the treatment additives can be added to heavily soiled laundry. If the laundry is only lightly soiled, only smaller amounts of treatment additives need to be added. A useless overdosing and an underdosing are thus effectively avoided. Heavily soiled laundry is treated with a sufficient amount of the at least one treatment additive. For example, this ensures that there is adequate disinfection in the case of heavily contaminated laundry.

Furthermore, it is provided that, after the at least one treatment additive has been added to the laundry, several measurements are carried out at specific, preferably regular, time intervals. During these measurements, the current content and / or the current concentration of the at least one treatment additive are measured. The measurements carried out at regular time intervals after the initial addition of the at least one treatment additive can be used to determine how quickly the added treatment additives are torn open. This is an indication of the degree of soiling of the laundry, so that if necessary, at least one treatment additive can be added in a targeted manner.

The method can be developed in such a way that immediately after the addition of the predetermined amount of the at least one treatment additive, the content of the same is measured and the time span or the time interval begins to run from the time of this measurement until the next measurement. The next measurement represents a re-measurement, whereby by comparison with the first measurement it is possible to determine which amount of the at least one treatment additive has already been consumed by the soiled laundry in the time elapsed between the two measurements. Based on the consumption determined between the successive measurements, the actual consumption can then be extrapolated depending on the degree of soiling of the laundry to be treated, preferably each individual item of laundry, and the at least one treatment additive can be replenished accordingly.

It is conceivable that after the measurement immediately following the addition of a first partial amount of the at least one treatment additive to the laundry, at least two further measurements are carried out at a specific, preferably the same time interval. Then, as it were, two or more than two re-measurements are carried out. This can be a trend of degradation of the initial determine the at least one treatment additive added, preferably a temporal course of the degradation of the at least one treatment agent and / or one Type of degradation of the specific laundry to be treated, in particular the respective laundry item.

Based on the chronological progression of the decrease in the at least one treatment additive since it was added to the laundry, a targeted subsequent metering of the at least one treatment additive is carried out. The time course of the decrease in the at least one treatment additive can preferably be used to calculate how high the total amount of the at least one treatment additive must be in order to be able to carry out an adequate wet treatment of the laundry. In particular, it can be determined in this way what total amount of detergents, disinfectants or other washing auxiliaries is required. For example, this also ensures that the laundry is completely disinfected.

The amount of the initially added treatment additive is subtracted from the total amount of the at least one treatment additive determined in order to arrive at the amount of the at least one treatment additive that, after the last measurement, in particular the last remeasurement, and / or the determination of the temporal course of the decrease in the at least a treatment additive is required since it was added to the laundry. In this way, targeted subsequent dosing can take place without any appreciable excess amounts of at least one treatment additive.

According to a preferred embodiment of the method, the at least one treatment additive is added to a treatment liquid with the laundry to be treated. During and / or during the addition, the at least one treatment additive is preferably mixed with the treatment liquid and the laundry contained therein. If it is not a liquid treatment additive, it can also be dissolved in the treatment liquid when it is mixed. The mixing and / or dissolving of the at least one treatment additive during and / or after the metering leads to a uniform concentration of the at least one treatment additive in the entire laundry item and the liquid bath containing the laundry item with the treatment liquid. As a result, the at least one measurement can lead to a representative average value of the concentration and / or the content of the at least one treatment additive in the laundry and the treatment liquid.

A further advantageous embodiment of the method provides that the at least one treatment additive of a treatment zone is a rotating or pivoting or rocking drivable elongated drum of a conveyor washing machine is added. The or each addition of the at least one treatment additive to the relevant treatment zone of the conveyor-type washing machine is preferably carried out during the rotating, pivoting and / or rocking movement of the drum. This promotes uniform mixing of the at least one treatment additive with the laundry and the treatment liquid in the relevant treatment zone of the drum of the conveyor-type washing machine.

It is conceivable to add the at least one treatment additive to a prewash zone and / or a main wash zone of the conveyor-type washing machine. In the prewash zone in particular, the laundry still contains a large part of the soiling or soiling that consumes the at least one treatment additive. Here it is particularly important to supply an amount of the at least one treatment additive corresponding to the degree of soiling of the current item of laundry in a targeted manner to the laundry and / or the treatment liquid, so that the at least one treatment additive is available to a sufficient extent for sufficient wet treatment of the laundry, but also no significant amount Overdose occurred.

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.

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

The conveyor-type washing machine 10 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 tunnel washing machines 10 with a smaller or larger number of consecutive chambers 14. This rotating drive can on done different 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. However, it is also conceivable to use a combination of a rotating or pivoting or rocking drive for the drum 11.

Several consecutive treatment zones are formed in the conveyor-type washing machine 10, namely, for example, a prewash zone, seen in the direction of passage 12, a subsequent main wash zone and, if appropriate, a rinsing zone and / or an aftertreatment zone behind it. An inlet funnel 16 of the conveyor-type washing machine 10 opens into the first chamber 14 of the prewash zone. Laundry is loaded into the first chamber 14 of the conveyor-type washing machine 10 via this. This first chamber 14 is at the same time 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 the wet-treated, namely at least washed, but possibly also rinsed and / or post-treated laundry, reaches the dewatering press 11 or some other dewatering device. In the dewatering press 11, 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 washing machine 10 then has no rinsing zone.

In the conveyor washing machine 10, the laundry is washed batchwise. For this purpose, in each chamber 14 of the conveyor-type washing machine 10 or, if necessary, only in some chambers 14 there is a batch of laundry with a larger amount of laundry.

The laundry is treated with treatment liquid in a bath in the conveyor washing machine 10, in particular washed and optionally rinsed and / or equipped. At least one treatment additive is added to the 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 14 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 an aftertreatment zone present in the conveyor-type washing machine 10. Different treatment additives can be added to the laundry in the individual zones, for example detergents in the prewash zone, neutralizing agents, finishing agents, bleaching agents and / or disinfectants in another zone.

The conveyor-type washing machine 10 has suitable measuring devices 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 possible to assign sampling lines from the relevant chamber 14 of the conveyor-type washing machine 10 to at least one filter, if necessary, and to assign the transducers 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 and accordingly controls or regulates the amount of the at least one treatment additive to be dosed or re-dosed accordingly .

If necessary, at least one measured value sensor can also be assigned to the dewatering press 11 if at least one treatment additive is also added to the washed laundry in the dewatering press. This is particularly true when the dewatering press 11 is also used to rinse the washed laundry.

The method according to the invention runs as follows with the conveyor washing machine 10 described above and the dewatering press 11 arranged downstream of it:
The laundry is washed in batches in the conveyor washing machine 10. For this purpose, there is preferably a batch of laundry 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 in the chambers 14 with treatment liquid. 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. In the dewatering press 11, too, at least one treatment additive can be added to the laundry which still has the bound liquor of the treatment liquid.

The addition of the at least one treatment additive to the laundry with the treatment liquid is preferably carried out with the drum 13 of the conveyor washing machine 10 driven in rotation, with the drum 13 driven in rotation or with drums 13 driven in rotation in opposite directions via pitch circular movements Drum 13.

For the following description of the method, it is assumed that a treatment additive, for example detergent, is added to the first chamber 14 of the conveyor washing machine 10, i.e. the first chamber of the prewash zone, during the rotating or pivoting or rocking rotation of the drum 13. As a result of the rotating or rocking or pivoting drive of the drum 13, the added treatment additive is mixed at least with the treatment liquid in the relevant chamber 14, preferably also the laundry of the laundry item in the chamber 14.

Initially, only a partial amount of the treatment additive is supplied to the first chamber with the item of laundry contained therein, including its treatment liquid. This partial amount of the treatment additive corresponds to the minimum amount that experience has shown is necessary for treating the least soiled laundry. On the basis of the known amount of the treatment additive added, the content or concentration of the treatment additive at the time of addition to the treatment liquid can be determined be closed with the laundry of the laundry item in question. However, it is also conceivable to measure the concentration and / or the content of the same in the treatment liquid of the laundry immediately after adding the minimum amount of the treatment additive.

According to the invention, after a certain and / or selectable time, in particular a time span and / or time interval, after the initial addition of the treatment additive, a measurement, preferably a further or repeated measurement, of the content of the treatment additive or its concentration in the liquid with the laundry is carried out in the first chamber 14. This measurement represents a first final measurement. At least on the basis of the result of the measurement carried out after the specified period of time, in particular a final measurement, in particular the amount of treatment additive consumed in the period of time is determined. On the basis of the time from the addition of the treatment additive to the measurement or re-measurement, the time course of the consumption of the treatment additive can be determined. The degree of soiling of the batch of laundry can be derived from this and the amount of treatment additive to be added, if necessary, can be determined. This amount, which corresponds to a remaining partial amount of the treatment additive that is still required, is then subsequently added to the treatment liquid with the batch of laundry in the first chamber 14 following the last measurement, in particular a final measurement, that is, it is replenished.

It is also conceivable not only to measure the remaining content or the concentration of the treatment additive once after a first period of time, or more precisely to measure it, but to carry out at least one further measurement. Then at least two re-measurements are carried out. This results in two time courses of treatment additive that is pulled up in the treatment liquid with the batch of laundry. These can be the same for the same time spans, but they can also be different. A small amount of the treatment additive is preferably consumed in the second period of time, that is to say until the second final measurement. From this it is possible to determine a tending, time-related consumption of the treatment additive and thus determine even more precisely how large the remaining partial amount of the treatment additive that may still have to be metered must be. It is also conceivable to choose a different length of time up to the first, the second or even each subsequent final measurement. This leads to a shorter procedure time, so that it can be determined more quickly whether and which amount of the treatment additive still needs to be topped up.

The method described above works in principle in exactly the same way if two or more different treatment additives are added and / or mixed in with the treatment liquid and the laundry item located therein in the same chamber 14. In this case, all treatment additives can be measured at the same time. Preferably, however, it is then provided to measure at least some treatment additives separately, so that each or at least some treatment additives can be metered separately in a targeted manner.

In principle, the method described above is also followed in order to carry out the required dosage of at least one treatment additive in at least one subsequent zone of the conveyor washing machine 10. This can be the main wash zone of a rinsing zone that may be present in the conveyor-type washing machine 10 and / or an aftertreatment zone of the conveyor-type washing machine 10. However, it is also conceivable to dose at least one treatment additive as required, accompanied by measurements, in the dewatering press 11 downstream of the conveyor washing machine 10 or some other dewatering device.

The invention is also suitable for other commercial washing machines, so it is not limited to the previously described exemplary embodiments with the conveyor washing machine 10. The invention can therefore also be used in other washing machines used in commercial laundries, for example washer extractors. In principle, the method according to the invention then proceeds in exactly the same way, except that metering is not carried out in at least one of the successive zones, but in at least one of the treatment phases of the washing machine that take place one after the other in the same, single chamber of the drum.

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 (10)

1. Method for a batchwise wet treatment of laundry in commercial washing machines, wherein a predetermined quantity of at least one treatment additive is added to the laundry at the beginning of the wet treatment and the current content of at least one treatment additive is measured at least once, characterized in that first of all only a minimum quantity of the at least one treatment additive, this minimum quantity always being necessary if laundry is only lightly soiled, is added to the laundry, at the end of a certain time period shortly after the addition of the minimum quantity of the at least one treatment additive, the current content of the at least one treatment additive is measured at least once, the consumption of the at least one treatment additive up until the measuring operation is determined therefrom in that, on the basis of the duration from the addition of the minimum quantity of the treatment additive up to the measuring operation which takes place shortly thereafter, the progression over time of the consumption of the treatment additive is determined and the degree of soiling of the batch of laundry is derived therefrom, and, on the basis of the consumption of at least one treatment additive, the quantity of the at least one treatment additive which, with account being taken of the degree of soiling determined for the batch of laundry, is possibly still to be metered in, is determined and, if appropriate, additional metering takes place.
2. Method according to Claim 1, characterized in that, following the addition of the at least one treatment additive, a number of measurements of the current content of the at least one treatment additive takes place at certain, preferably regular, time intervals.
3. Method according to Claim 1 or 2, characterized in that, immediately following the initial addition of a predetermined sub-quantity of the at least one treatment additive, the content thereof is measured and, from the point in time of this measuring operation, the time period to the next measuring operation begins to run.
4. Method according to one of the preceding claims, characterized in that, following the first measurement of the consumption of at least one treatment additive, at least one further measurement takes place following a certain time period.
5. Method according to one of the preceding claims, characterized by determination of the difference in the at least one treatment additive between successful measurements, preferably successive follow-up measurements.
6. Method according to Claim 5, characterized in that the difference in the content determined on the basis of at least one measurement and/or follow-up measurement in relation to the original, or previously measured, content of at least one treatment additive is used to determine a progression over time of the decrease in content and/or concentration of the at least one treatment additive.
7. Method according to Claim 6, characterized in that the progression over time of the decrease in concentration and/or content of the at least one treatment additive is used to determine whether additional metering is necessary and, if appropriate, specific additional metering of the at least one treatment additive is carried out.
8. Method according to one of the preceding claims, characterized in that the at least one treatment additive is added in a treatment liquid in which the laundry is located, preferably the at least one treatment additive is mixed with the treatment liquid, and possibly dissolved in the treatment liquid, when the treatment liquid is added and/or while it is being added.
9. Method according to one of the preceding claims, characterized in that the at least one treatment additive is added to a relevant treatment zone of a rotationally drivable elongate drum (13) of a continuous washing machine (10), preferably while the drum (13) is being driven in a revolving and/or pivoting manner.
10. Method according to one of the preceding claims, characterized in that the at least one treatment additive is added in the pre-wash zone and/or in the final-wash zone of the continuous washing machine (10) and possibly to a rinse zone and/or aftertreatment zone of the continuous washing machine (10) .

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