EP3896143A1 - Method for wet treating laundry - Google Patents

Abstract

Laundry, especially if it can be contaminated, is disinfected when it is washed. For this purpose, a disinfectant is added to the treatment liquid. This addition has so far been based on empirical values, with an overdose taking place to be on the safe side. As a result, excess disinfectant gets into the wastewater with the treatment liquid used. That is polluting. In addition, too much disinfectant is required, which unnecessarily increases the costs of disinfection. The invention provides, at least after washing, to take a sample of the treatment liquid used and to measure whether this treatment liquid still contains a residual disinfectant and how much it is possibly is. Adequate disinfection can only be assumed if the measurement shows that the treatment liquid used still contains a minimum amount of disinfectant. In this way, the method according to the invention contributes to increasing the safety of disinfection without unnecessary overdosing of disinfectant.

Description

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

The wet treatment of laundry is usually carried out by washing, rinsing and optionally at least one aftertreatment, which can be, for example, finishing the washed and rinsed laundry. In particular, contaminated laundry must also be disinfected.

In laundries where laundry from, for example, hospitals, retirement homes, hotels or the like is to be washed, the laundry must be completely disinfected so that only sufficiently disinfected, sterile laundry leaves the laundry.

In order to ensure adequate disinfection of the laundry, it has hitherto been customary to carry out the disinfection with an overdose of disinfectants in order to ensure adequate disinfection. The excess disinfectant then reaches the drain with the first treatment liquid, which is in particular washing water with detergent additives. That is polluting. Overdosing also causes unnecessary costs.

Proceeding from the above, the invention is based on the object of creating a method for the wet treatment of laundry which allows reliable disinfection without, or at least without, any significant overdosing of disinfectants.

A method serving to solve this problem has the measures of claim 1. According to this method, it is provided that the at least one disinfectant is measured, in particular with regard to the amount and / or the concentration in the treatment liquid, at least after and / or before the disinfection. If, after disinfection is complete, a minimum content of disinfectant, which serves as a safety buffer, is measured, this is an indication of reliable and complete disinfection. The result is that the laundry subjected to the wet treatment is sterile. If no disinfectant or insufficient residual disinfectant is measured after washing, this indicates the risk of inadequate disinfection. The laundry must then be subjected to at least one extended or subsequent disinfection. If, as an alternative or in addition, the disinfectant is measured before the start of the disinfection and too little disinfectant is found, a corresponding additional metering of the at least one disinfectant can take place before the start of the disinfection process.

In terms of the method, provision is preferably made for at least the disinfectant to be added to the treatment liquid, so that the disinfection takes place during the wet treatment, in particular during washing, of the laundry. The concentration of the disinfectant in the treatment liquid is then measured after and / or before the disinfection. By measuring the concentration of the disinfectant in the treatment liquid, which is used in particular for washing, meaningful measurement results are obtained that allow a reliable assessment of whether the concentration of the disinfectant in the treatment liquid is sufficient for complete disinfection of the laundry and / or a minimal residual concentration after the disinfection of disinfectant is present in the treatment liquid, which indicates safe disinfection.

An advantageous further development of the method provides that the laundry is washed in a pre-wash and a subsequent clear wash and the disinfection of the laundry takes place in the clear wash. It is then particularly advantageous to determine the concentration of the at least one disinfectant in the treatment liquid, in particular the main wash liquid, after and / or before the main wash.

If the concentration of the disinfectant is determined only after the clear wash, the measured residual concentration of the disinfectant is used to determine whether the disinfection was able to take place sufficiently, namely when the measured residual concentration after the clear wash corresponds to a predetermined limit value or is above. If, as an alternative or in addition, the concentration of the disinfectant in the treatment liquid is measured before the main wash, then, if necessary, disinfectant can be added during the main wash before the start of the disinfection of the laundry. This additional metering takes place when the concentration of the disinfectant in the main wash liquid measured before the main wash is below a predetermined limit value.

Provision is preferably made for the pre-wash to take place with a treatment liquid used for this purpose, the pre-wash liquid, and the clear wash with another treatment liquid used for the clear wash. The disinfectant is then added after the laundry has been at least largely separated from the free prewash liquid and the main wash liquid used for the main wash.

According to an advantageous development of the method, it is provided that the measurement of the concentration of the disinfectant in the treatment liquid, in particular the main wash liquid, is measured with at least one sensor. The concentration of at least one sensor is preferably measured according to the flow principle. As a result, a multiple, repeated and / or continuous measurement of the concentration of the disinfectant in the treatment liquid, in particular the main wash liquid used for the main wash, can take place. The sensor is one that is designed to measure the disinfectant in question.

Furthermore, it can preferably additionally or alternatively be provided that the measurement of the concentration of the disinfectant in the treatment liquid takes place at a specified temperature. For example, it is that temperature which the main wash liquid with the disinfectant added to it should have at least at the beginning of the main wash. This temperature is preferably a constant 35 ° C. or, if appropriate, up to 5 ° C. above or below. Because the measurement result of the sensors for determining the concentration of the disinfectant is heavily dependent on the temperature, the measurement at a predetermined, preferably constant temperature measurement results that are comparable to specified values.

It is possible to design or develop the method in such a way that different disinfectants, which are used, for example, alternatively depending on the type of laundry, degree of soiling or the type of soiling, are measured with different sensors, namely sensors that are used to individually determine the special disinfectant provided, are particularly suitable. A specific measurement of the concentration of the disinfectant used can then be measured by the sensor intended for this purpose. The measurement is carried out with sensors that are provided for the chemical type and / or the composition of the respective disinfectant.

In an advantageous embodiment of the method, before and / or after the disinfection of the laundry, a small amount sufficient to measure the concentration of the disinfectant in the treatment liquid is taken as a sample and used for the measurement with the sensors. For this purpose, before and / or after the disinfection, the treatment liquid containing the disinfectant is branched off from the wash liquor, in particular the main wash liquor. As a result, only a small amount of the treatment liquid containing the respective disinfectant, namely the sample, needs to be prepared for measurement and fed to the respective sensor or passed along it. As a result, the measurement and thus control of the amount, in particular the concentration, of the disinfectant in the treatment liquid can be carried out quasi "in situ".

According to an advantageous embodiment of the method, it is provided that the sample branched off from the treatment liquid with the disinfectant contained therein is first filtered before it is fed to the at least one sensor or guided along it. A single filtration can be sufficient, which is then a fine or ultra-fine filtration. Preferably, however, a prefiltration takes place first, for example lint separation, and then a finer filtration. The fine filtration can be fine filtration, ultrafine filtration and / or microfiltration. As a result of the previous at least one-time filtering of the sample, specifically only the sample, the disinfectant-containing treatment liquid to be measured by the at least one sensor is measured without interfering accompanying substances. This will affect the sensors, blockages or other malfunctions in the Measurement of the concentration of the disinfectant prevented, especially if the measurement works according to the flow principle.

According to another possible embodiment of the method, if the concentration of the disinfectant in the treatment liquid is too low, measured after washing, preferably after the clear wash, the wash, preferably clear wash, is continued for a predetermined post-disinfection period. The disinfection then takes place longer than intended if the concentration of disinfectant in the treatment liquid, preferably the main wash liquid, is low. As a result of the disinfection phase being prolonged when the disinfectant concentration is too low, the entire disinfection is nevertheless carried out completely in this way.

Another alternative or additional embodiment of the method provides for an amount of disinfectant to be added to the treatment liquid before the start of re-disinfection that corresponds to the minimum concentration of disinfectant in the treatment liquid, preferably at the end of the wash, in particular the clear wash, or is a certain percentage higher. This contributes to a sufficient disinfection of the laundry under all circumstances, even if no more disinfectant was measured in the treatment liquid after the end of the initial disinfection.

In an advantageous further development of the method, the pH value of the treatment liquid with the disinfectant still present in it can be measured at least after the wash, preferably after the clear wash. In particular, the sample with which at least one sensor determines the concentration of the disinfectant in the treatment liquid is also used for this measurement. The measurement of the pH value of the treatment liquid with the disinfectant contained therein preferably takes place after the measurement of the concentration of the disinfectant with at least one corresponding sensor in the sample. This procedure is based on the knowledge that the measured value obtained when measuring the concentration of the disinfectant in the treatment liquid is dependent on the pH value of the treatment liquid containing the disinfectant. With the additional measurement of the pH value, the measured value for the concentration of the disinfectant can be calibrated so that measured values that are comparable to the target values can be obtained. This ensures great accuracy, reliability and informative value of the before and / or after the washing process, in particular the main wash process, measured concentration of at least the disinfectant in the treatment liquid.

Fig. 1

eine schematische Darstellung eines Teils einer eine Durchlaufwasch-maschine aufweisenden Vorrichtung zur Durchführung des Verfahrens, und

Fig. 2

eine detailliertere Darstellung der Vorrichtung in einem Querschnitt durch die Durchlaufwaschmaschine der Fig. 1.

An embodiment of a possible device for carrying out the method is explained in more detail below with reference to the drawing. In this show:

Fig. 1

a schematic representation of part of a device having a conveyor-type washing machine for carrying out the method, and

Fig. 2

a more detailed representation of the device in a cross section through the conveyor washing machine of Fig. 1 .

The following description relates to the disinfection of laundry during the wet treatment of the same in a conveyor washing machine 10 for commercial laundries. The laundry to be treated wet, namely to be washed and disinfected, is not shown in the figures. The laundry can be all types of textiles that have to be disinfected, in particular items of clothing, work clothing, flat laundry, but also dirt control mats or the like.

The one in the Fig. 1 Continuous washing machine 10, shown schematically in a side view, has a drum 12 which can be driven to rotate or pivot (to and fro) about a preferably horizontal axis of rotation 11. The axis of rotation 11 runs centrally through drum 12, preferably horizontally. The laundry is transported in batches in the flow direction 13 through the rotating or pivoting driven cylindrical drum 12.

A plurality of chambers 15 which follow one another in the direction of passage 13 are formed in the drum 12 by means of transversely directed, circular or annular partition walls 14. The chambers 15 can be of the same size, but also of different sizes. The one in the Fig. 1 The conveyor washing machine 10 shown has a total of thirteen successive chambers 15. The method according to the invention is not limited to this. It can also be carried out with conveyor washing machines 10 which have a larger or smaller number of successive chambers 15.

The one in the Fig. 1 The conveyor washing machine 10 shown has three treatment zones following one another in the direction 13 of the conveyor. Each treatment zone extends over several successive chambers 15, wherein the number of successive chambers 15 per treatment zone can be different or the same. The treatment zones are a pre-wash zone 16, a main wash zone 17 following in the flow direction 13, and a rinsing zone 18 behind the main wash zone 17. In the conveyor-type washing machine 10 described here, the main wash zone 17 simultaneously disinfects the laundry during the main wash. An aftertreatment zone, for example a finishing zone and / or neutralization zone, can be integrated into the rinsing zone 18.

The conveyor washing machine 10 is followed by one in the Fig. 1 dewatering device not shown, for example a dewatering press or a dewatering centrifuge. The drainage device can also be used for rinsing and, if necessary, post-treatment of the pre-washed, clear-washed and disinfected laundry. Then the conveyor-type washing machine 10 does not need to have a rinsing zone 18.

The drum 12 of the conveyor washing machine 10 is assigned several stationary and liquid-impermeable external drums. A first outer drum 19, seen in the direction of passage 13, is located at the end of the prewash zone 16. A second outer drum 20 is arranged at the beginning of the main wash zone 17. At the end of the main wash zone 17, a third outer drum 21 is provided. A fourth outer drum 22 is located at the beginning of the rinsing zone 18 and a fifth (last) outer drum 23 at the end of the rinsing zone 18. Fig. 2 ). The respective outer drum 19 to 23 extends over the full length of a chamber 15. In the areas of such chambers 15 to which no outer drum 19 to 23 are assigned, the outer surface of the drum 12 is impermeable to liquids.

A loading chute 24 is located in front of the drum 12, with which the conveyor-type washing machine 10 is loaded in batches by the dirty and possibly also contaminated laundry reaching the first chamber 15 of the pre-washing zone 16 of the conveyor-type washing machine 10 via the loading chute 24. At the end of the conveyor washing machine 10, an unloading chute 25 is provided. Via the discharge chute 25, the washed, disinfected and optionally rinsed laundry leaves the last chamber 15 of the conveyor washing machine 10 in batches so-called bound liquor, the drainage device, not shown, are fed.

In the illustrated conveyor-type washing machine 10, a sampling line 26 branches off from the second outer drum 20 at the beginning of the main wash zone 13. A second sampling line 27 branches off from the third outer drum 21 at the end of the main wash bowl 17. In each sampling line 26 and 27 there is a shut-off valve 28, 29. As a result, both sampling lines 26 and 27 can be closed or a sampling line 26 or 27 can be opened alternately. At a collection point 30, the ends of the sampling lines 26 and 27 located behind the shut-off valves 28 and 29 meet, from there to a common, in particular single, flow line 34 to a pump 31, from there through at least one filter 32 and from the filter 32 a flow measuring device 33 to be transported.

The one in the Fig. 1 It is possible, if necessary, to take samples of the treatment liquid with the at least one of these added disinfectants before and / or at the beginning of the main wash zone 17 and at the end or after the main wash zone 17 through the sampling lines 26 and 27. Alternative designs of the conveyor-type washing machine 10 are also conceivable, in which only a single sampling line 26 or 27 branches off from the second outer drum 20 or the third outer drum 21. Then, in contrast to the representation in the Fig. 1 The concentration of the disinfectant in the treatment liquid cannot be measured at the beginning and at the end of the main wash zone 17, but either the concentration of the disinfectant in the treatment liquid before or at the beginning of the main wash zone 17 or at the end or after the main wash zone 17.

the Fig. 2 shows the flow measuring device 33 in more detail in connection with a cross-section through the drum 12 of the conveyor-type washing machine 10 in the area of the third outer drum 21 behind or at the end of the main wash zone 17. Here, when the shut-off valve 28 is open from the sampling line 26, the sample of a small enough sample that is sufficient for analysis flows Amount of treatment liquid with disinfectant in the flow line 34. The sample flows through the filter 32, a subsequent buffer tank 35 and an open shut-off valve 36 to reach the pump 31. The pump 31 conveys the sample containing the disinfectant to be measured through the flow measuring device 33.

In the Fig. 2 an embodiment of the flow measuring device 33 is shown in detail. Accordingly, the flow measuring device 33 has two flow cells 37 and 38 which follow one another at a distance in the flow direction of the sample through the flow line 34. The flow cells 37, 38 represent a small tank or reservoir for at least part of the treatment liquid serving as a sample with the disinfectant mixed therein of the sample and the rest of the sample flows through the respective flow cell 37, 38 during the measurement. A continuous measurement of the sample then takes place as it passes through the respective flow cell 37, 38.

In the exemplary embodiment shown, the first flow cell 37 following the pump 31 in the direction of flow of the sample is assigned three measured value pickups, preferably those designed as sensors, namely a conductance sensor 39, a temperature sensor 40 and a pH value sensor. Sensor 41.

The second flow cell 38 following the flow cell 37 in the flow direction of the sample is assigned at least one sensor for a specific disinfectant. If the disinfectant is peracetic acid, the sensor is designed to measure the concentration of peracetic acid in the sample made up of the treatment liquid and disinfectant. If hydrogen peroxide is used as the disinfectant, the disinfectant sensor 42 is designed to measure hydrogen peroxide. In the case of chlorine as the disinfectant, the disinfectant sensor 42 is a chlorine sensor. Matched disinfectant sensors 42 could also be used for other disinfectants. If the disinfection is only carried out with a single specific disinfectant, the sensor only needs to be suitable for measuring the concentration of this disinfectant. If different disinfectants are optionally used, the disinfectant sensor 42 is designed in such a way that it allows, for example by switching, a measurement of all of these disinfectants with regard to the concentration thereof in the treatment liquid. Alternatively, it is conceivable to assign several different disinfectant sensors 42 to the flow cell 38, specifically one disinfectant sensor 42 for the particular disinfectant used.

In the embodiment of Fig. 2 a pH value sensor 43 and / or temperature sensor 44 are also assigned to the flow cell 38. But these are only optional, so not absolutely necessary, especially not if the first flow cell 37 already has such sensors. It is conceivable to assign a temperature sensor 40, 44 or pH value sensor 41, 43 only to flow cell 37 or flow cell 38. The conductance sensor 39, the temperature sensor 40, 44 and / or the pH value sensor 41, 43 can also be provided at least simply at another point on the conveyor-type washing machine 10. No temperature sensors 40, 44, pH value sensors 41, 43 and / or conductivity sensors 39 are then assigned to the flow cells 37 and 38.

In the embodiment of Fig. 2 a mixer 45, in particular a static mixer, is provided between the flow cells 37, 38. This serves to mix the treatment liquid and the disinfectant in the sample before the sample in the flow cell 38 is measured by the respective disinfectant sensor 42 with regard to the concentration of the at least one disinfectant in the sample. The mixer 45 can also be provided in front of the first flow cell 37. It is also conceivable to provide a mixer 45, possibly also different types of mixers, in front of each flow cell 37 and 38.

Furthermore, the Fig. 2 it can be seen that two outlets are provided behind the second flow cell 38, namely an outflow 46 for discharging the sample into a sewer and an outflow 47 for returning the sample to that chamber 15 of the conveyor washing machine 10, which the third outer drum 21 behind the main wash zone 17 is assigned. Both outlets 46 and 47 are provided with a shut-off valve 48, 49 for the optional shut-off or release of the respective outflow 46, 47.

A flow meter 50 can be assigned to the drain 47 returned to the conveyor washing machine 10. With this, the flow of the sample through the flow cells 37 and 38 and the drain 47 can be determined. For example, the flow rate of the sample is 5 to 30 liters per hour, in particular 10 to 20 liters per hour.

In the embodiment of Fig. 2 an optional fresh water inlet 51 is provided. A pump, in particular a metering pump 52, and a shut-off valve 53 are assigned to this. As a result, fresh water of a specific quantity can be fed to the sample between the two flow cells 37, 38 as required. This can happen, for example, if the temperature sensor 40 of the first flow cell 37 detects an excessively high temperature of the sample, which should preferably be between 30 ° and 40 °, in particular 32 ° to 38 °. Then the high temperature can be reduced to the predetermined or optimal temperature by supplying a corresponding amount of fresh water, if from Temperature sensor 40 of the first flow cell 37 a too high temperature of the sample is determined. The temperature sensor 44 of the subsequent flow cell 38 then measures the cooled sample produced by adding cold fresh water to determine whether the temperature of the sample after the metered addition of fresh water is at the intended and / or optimal temperature for measuring the concentration of the disinfectant in the sample.

The one in the Fig. 2 The flow measuring device 33 shown measures the concentration of the disinfectant in the sample of treatment liquid and remaining disinfectant after the disinfection is complete, namely at the end of the main wash zone 17, where the third outer drum 21 is located. Alternatively or additionally, the Fig. 2 In connection with the third outer drum 21 behind the main wash zone 17, the flow measuring device 33 with its additional components can also be provided in the area of the second outer drum 20 in front of the main wash zone 17. Then the concentration of the disinfectant in the treatment liquid is determined only or also (additionally) before the final wash, whereby it can be determined whether the treatment liquid contains enough disinfectant to adequately disinfect the laundry. If this is not the case, before the final wash, the concentration of the same in the treatment liquid can be increased to the intended target concentration by adding at least one disinfectant.

If as shown in the Fig. 1 the concentration of the disinfectant before and after the main wash zone 17 is measured by the single flow measuring device 33, is that in FIG Fig. 2 A sample can also be supplied from the area of the second outer drum 20 in front of the main wash zone 17. Then, as shown in the Fig. 2 in front of the filter 32 in the Fig. 1 illustrated collection point 30, via which optionally at least one sample from the second outer drum 20 in front of the main wash zone 17 or the third outer drum 21 behind the main wash zone 17 to the only one in the Fig. 2 The flow measuring device 33 shown and its additional components can be supplied by appropriately actuating the shut-off valves 28, 29 in the sampling lines 26 and 27, respectively.

The filter 32 is designed in such a way that it has a filter quality which ensures that measurement results can be determined by the sensors in the flow cells 37, 38 which cannot be impaired by the components to be filtered out in the sample. The filter 32 is preferably a fine filter, in particular a very fine filter with at least one filter membrane. Alternatively, it is also conceivable instead of a filter 32 provide several successive filters that allow multi-stage filtration, in particular with different filter grades. For example, a coarse filter and a subsequent fine filter, in particular a very fine filter, are then provided.

The method according to the invention for disinfecting laundry during wet treatment is explained below in connection with the device described above:
The method according to the invention relates to the wet treatment of laundry of any kind, the laundry being at least washed and disinfected. Disinfection preferably takes place when washing the laundry. The laundry is washed and disinfected at the same time. For this purpose, a corresponding amount of at least one disinfectant is mixed into the treatment liquid of the laundry.

According to the invention, the method is designed in such a way that a check is carried out to determine whether the disinfection of the laundry has taken place and / or can take place to a sufficient extent, preferably completely, so that the disinfected laundry can be classified as sterile. According to the method, this check of the completeness of the disinfection is carried out during the washing process, in particular during the clear wash. The completeness of the disinfection is checked "in situ". This makes it possible - if necessary due to the measurement - to either add more disinfectant or to extend the disinfection process over the intended period by a certain empirically determined and / or calculated period of time.

Although it is preferred to check the disinfection process during the main wash, it is also conceivable to check the completeness of the disinfection during other phases of the wash process. It is also conceivable to check the completeness of the disinfection when rinsing the washed laundry and / or when treating the laundry afterwards, for example in a bleaching and / or finishing zone.

For the following description, it is assumed that the disinfection takes place in the main wash zone 17 of the conveyor washing machine 10 and the disinfection check, in particular the completeness of the disinfection, takes place at the end of the main wash zone 17. Then, from the third outer drum 21 assigned to the last chamber 15 of the main wash zone 17, a small amount of treatment liquid, namely main wash liquid, with the remaining ideally still present therein Disinfectant taken as a sample. The volume of this sample is only as large as required for the automatic measurement of the remaining proportion of disinfectants in the treatment liquid. For example, a few liters of the treatment liquid, namely the main wash liquid, with the remaining disinfectant still present therein, are sufficient as the sample to be measured.

After the sample has been filtered in the at least one filter 32, the filtered sample is pumped into the first flow cell 37 by the pump 31. Here, the temperature and / or the pH value are usually measured by the temperature sensor 40 or pH value sensor 41 in the flow, preferably continuously. Additionally or alternatively, the conductance sensor 39 can also measure the conductance of the sample, that is to say of the treatment liquid with the remainder of the disinfectant preferably still contained therein. Because at least the temperature and / or the pH value of the sample can influence the measurement of the concentration of the disinfectant in the treatment liquid, a measured value compensation and / or correction can take place on the basis of the measured temperature and / or the pH value. This prevents the measured value of the concentration measured in the subsequent second flow cell 38 or, in particular, the residual concentration of the disinfectant being falsified at different temperatures and / or pH values in the sample and thus meaningful measured values for the treatment liquid after disinfection any remaining disinfectant is present. If the conductance of the treatment liquid with the disinfectant still present therein is also determined by the conductance sensor 39 in the first flow cell 37, this can further improve the measurement result, particularly in the case of certain disinfectants.

The sample leaving the first flow cell 37 is mixed again in the mixer 45 in order to bring about a uniform distribution of the remaining disinfectant in the treatment liquid, in particular the main wash liquid at the end of the main wash zone 17. As a result, the sample reaches the second flow cell 38 in a homogeneously mixed state.

In the second flow cell 38 - as in the first flow cell 37 - when the sample flows through, at least the concentration of the remaining at least one disinfectant in the treatment liquid or the main wash liquid is measured, preferably continuously. This is done with at least one disinfectant sensor tailored to the respective disinfectant. This is a sensor that measures the residual concentration of the disinfectant, for example peracetic acid, hydrogen peroxide and / or chlorine. Unless one disinfectant sensor 42 is suitable or switchable for measuring different disinfectants, several disinfectant sensors 42 provided for different disinfectants are assigned to the flow cell 38 when different disinfectants are to be measured.

A pH value sensor 43 and / or a temperature sensor 44 can optionally also be assigned to the second flow cell 38. These additional sensors are useful, for example, when cold fresh water is added to the sample upstream of the second flow cell 38 so that the sample for measurement in the second flow cell 38 has the intended desired temperature and / or the intended pH value.

If, when measuring the remaining proportion of the at least one disinfectant in the treatment liquid, in particular the main wash liquid used for the main wash, it is determined that there is still residual disinfectant in the treatment liquid, this indicates sufficient disinfection of the laundry, especially after the main wash. It is also possible to specify a minimum concentration of the disinfectant after the disinfection process in order to increase the reliability of a complete disinfection. The concentration of the disinfectant in the treatment liquid at the end of the main wash zone is then determined by the at least one disinfectant sensor 42 and compared with the predetermined minimum residual concentration.

If the above-described check of the completeness of the disinfection shows that there is no more disinfectant in the treatment liquid after the disinfection process or that the residual concentration of the disinfectant is below a specified limit value, this is an indication of incomplete disinfection. If the residual concentration of the disinfectant in the treatment liquid is too low, the disinfection time can be extended by lengthening the disinfection of the laundry or re-disinfecting it with the remaining disinfectant until the laundry is completely disinfected. If, however, no more disinfectant at all is measured in the treatment liquid after the disinfection process, disinfectant must be replenished with the treatment liquid in the main wash zone 17 and then replenished. For this purpose, the laundry is cleaned with the added disinfectant post-treated until it is completely disinfected - possibly after another measurement of the residual concentration of the disinfectant in the treatment liquid.

The method according to the invention also makes it possible, alternatively or additionally, to measure the concentration of the at least one disinfectant in the treatment liquid in the area of another point on the drum 12 of the conveyor washing machine 10, in particular on at least one other outer drum 19, 20, 22 and / or 23 .

In the representation of the Fig. 1 It is provided that a sample of the treatment liquid, in particular the clear wash liquid, with this added, at least one disinfectant, is branched off from the second outer drum 20 assigned to it, also before the main wash, i.e. at the beginning of the main wash zone 17, and from it via the sampling line 26 and the collection point 30 of the pump 31 through the at least one filter 32 and then through the flow measuring device 33, namely the flow cell 37 and the flow cell 38. Here the measurement of the concentration of the at least one disinfectant in the still unused main wash liquid takes place exactly as described in connection with the measurement of the concentration of the remaining disinfectant in the used treatment liquid, in particular the main wash liquid. The concentration of the at least one disinfectant in the unused treatment liquid prior to disinfection is only measured before the main wash zone 17, namely when all of the disinfectant required and intended for disinfection is still bound in the treatment liquid. The concentration of the at least one disinfectant in the treatment liquid measured upstream of the main wash zone 17 is compared with a target concentration. If the measured concentration is below the target concentration, the missing amount of the at least one disinfectant is added before the start of the main wash and thus also the disinfection process. Thereafter, if the concentration of the at least one disinfectant in the treatment liquid, in particular the main wash liquid, has been measured again, the disinfection process can begin.

It is also conceivable to only measure the concentration of the at least one disinfectant in the treatment liquid before the final wash if it can be assumed that the initial concentration will be the same under all circumstances the at least one disinfectant in the treatment liquid is sufficient to completely disinfect the laundry.

The method according to the invention was described below in connection with a conveyor washing machine 10 for commercial laundries. In principle, however, the method can be used in the same way in connection with other washing machines, in particular washer-extractors, in particular those that are also used in commercial laundries. List of reference symbols: 10 Conveyor washing machine 42 Disinfectant sensor 11 Axis of rotation 43 pH value sensor 12th drum 44 Temperature sensor 13th Flow direction 45 mixer 14th partition wall 46 Drain 15th chamber 47 Drain 16 Pre-wash zone 48 Shut-off valve 17th Main wash zone 49 Shut-off valve 18th Rinsing zone 50 Flow meter 19th first outer drum 51 Fresh water inlet 20th second outer drum 52 Dosing pump 21 third outer drum 53 Shut-off valve 22nd fourth outer drum 23 fifth outer drum 24 Loading chute 25th Discharge chute 26th Sampling line 27 Sampling line 28 Shut-off valve 29 Shut-off valve 30th Collection point 31 pump 32 filter 33 Flow meter 34 Flow line 35 Buffer tank 36 Shut-off valve 37 Flow cell 38 Flow cell 39 Conductivity sensor 40 Temperature sensor 41 pH value sensor

Claims (11)

Method for the wet treatment of laundry, wherein the laundry is at least washed in a treatment liquid and the laundry is disinfected with disinfectant, characterized in that the disinfectant is measured at least before and / or after the disinfection. Method according to claim 1, characterized in that the laundry is disinfected with at least one disinfectant in the treatment liquid and the concentration of the at least one disinfectant in the treatment liquid is measured before and / or after the disinfection. Method according to claim 1 or 2, characterized in that the laundry is washed with a pre-wash and a clear wash and the laundry is disinfected during the clear wash. Method according to one of the preceding claims, characterized in that a pre-wash is carried out in a treatment liquid used for this purpose, in particular a pre-wash liquid, and the final wash in another treatment liquid used for this purpose, in particular a clear wash liquid, the at least one disinfectant being added to the treatment liquid used for the clear wash. Method according to one of the preceding claims, characterized in that the concentration of the at least one disinfectant is measured with at least one sensor, preferably using the flow principle, in particular at a fixed constant temperature. The method according to any one of the preceding claims, characterized in that the concentration of the respective disinfectant in the treatment liquid is measured with at least one sensor for a respective particular disinfectant, wherein preferably different sensors are provided for example depending on the type of laundry, the concentration of the Measure the respective disinfectant used in the treatment liquid in a targeted manner. Method according to one of the preceding claims, characterized in that, before and / or after the disinfection of the laundry, a sufficient small amount of the total treatment liquid containing the disinfectant for washing, preferably clear washing, to measure the concentration of the at least one disinfectant in the treatment liquid, serving treatment liquid is branched off with the disinfectant still present therein. Method according to Claim 7, characterized in that the branched off sample of a small amount of the treatment liquid containing the disinfectant is first filtered at least once before it is fed to the at least one sensor. Method according to one of the preceding claims, characterized in that if the concentration of the at least one disinfectant in the treatment liquid is too low measured after washing, preferably clear washing, washing, preferably clear washing, is continued for a post-disinfection period. Method according to Claim 9, characterized in that, before the start of the subsequent disinfection of the treatment liquid, an amount of disinfectant is added that corresponds to the minimum concentration of the at least one disinfectant in the treatment liquid at the end of the wash, preferably clear wash, and / or at the end of the disinfection process. Method according to one of the preceding claims, characterized in that at least before and / or after washing, preferably after the clear wash, the pH value of the treatment liquid is measured with the at least one disinfectant that may still be present therein, in particular also the sample for this measurement is used.

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