EP3896143B1 - Method for wet treating laundry - Google Patents

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, if appropriate, at least one aftertreatment, which can involve, for example, finishing the washed and rinsed laundry. Contaminated laundry in particular 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 flows into the drain with the first treatment liquid, which is in particular washing water with detergent additives. This is bad for the environment. Overdosing also causes unnecessary costs.

From the EP 3 219 842 A1 a method for the wet treatment of laundry is known, which provides for measuring the current content of at least one treatment additive, which can also be a disinfectant, during the wet treatment. Based on the consumption of the at least one treatment additive up to the time of the measurement, the amount of the treatment additive that may still have to be metered in is determined.

The DE 39 16 910 A1 and the DE 44 12 576 A1 disclose various measurement or sensor systems for dosing disinfectants. The content of a specific, not yet used disinfectant in the treatment liquid is determined.

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 a significant overdosing of disinfectants.

A method serving to solve this problem has the measures of claim 1 . According to this method, provision is made for the at least one disinfectant to be measured, in particular with regard to the quantity and/or the concentration in the treatment liquid, at least after or before and after the disinfection.

If, after completion of the disinfection, a minimum content of disinfectant, which serves as a kind of safety buffer, is measured, this is an indication of a reliable and complete disinfection. The consequence is that the laundry subjected to the wet treatment is sterile. If no or too little residue of disinfectant is measured after washing, this indicates the risk of insufficient disinfection. The laundry must then be subjected to at least one prolonged disinfection. If, in addition, the disinfectant is measured before the start of the disinfection and too little disinfectant is determined, a corresponding replenishment of the at least one disinfectant can take place before the start of the disinfection process.

It is provided to measure different disinfectants, which are used alternatively depending on the type of laundry, degree of soiling or the type of soiling, with different sensors, specifically sensors that are provided, particularly suitable, for the individual determination of the specific disinfectant. A targeted 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 addition, according to the method, if the concentrations of the disinfectant in the treatment liquid measured after the wash, preferably after the main wash, are too low, the wash, preferably main wash, is continued for a predetermined post-disinfection period.

The disinfection then takes place with a low concentration of disinfectant in the treatment liquid, preferably Main wash liquid, longer than intended. Due to the extended disinfection phase when the disinfectant concentration is too low, the entire disinfection is nevertheless carried out completely in this way.

According to the method, at least the disinfectant is added to the treatment liquid, so that the disinfection takes place during the wet treatment, in particular during washing, of the laundry. Then the concentration of the disinfectant in the treatment liquid is measured after or before and after 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 which 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 whether there is still a minimal residual concentration after the disinfection of disinfectant is present in the treatment liquid, which indicates reliable disinfection.

An advantageous further development of the method provides that the laundry is washed in a prewash and a subsequent main wash and the laundry is disinfected during the main 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 only determined after the main 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 main wash corresponds to or exceeds a predetermined limit value. If, in addition, the concentration of the disinfectant in the treatment liquid is measured before the main wash, then, if necessary, disinfectant can be replenished before the start of the disinfection of the laundry during the main wash process. This subsequent dosing 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 be carried out with a treatment liquid serving for this purpose, the pre-wash liquid, and for the final wash to be carried out with another treatment liquid for the main wash. The disinfectant is then added after the laundry has been separated, at least for the most part, from the free prewash liquid and the main wash liquid used for the main wash.

According to the invention, it is provided that 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-through principle. As a result, a multiple, repeated and/or continuous measurement of the concentration of the disinfectant in the treatment liquid, especially 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 the temperature that 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 optionally up to 5°C above or below. Because the measurement result of the sensors for determining the concentration of the disinfectant is highly dependent on the temperature, the measurement at a predetermined, preferably constant, temperature results in measurement results that are comparable to predetermined values.

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 measurement with the sensors. For this purpose, before and/or after the disinfection, the treatment liquid containing the disinfectant is diverted 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 the measurement and fed to the respective sensor or passed along it. As a result, the measurement and thus control of the quantity, 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 diverted 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 superfine filtration. However, a pre-filtration, for example lint separation, preferably takes place first, followed by a finer filtration. At the Fine filtration can be fine filtration, ultrafine filtration and/or microfiltration. By filtering the sample at least once beforehand, and specifically only the sample, the treatment liquid to be measured by at least one sensor and containing disinfectant is measured without interfering accompanying substances. This prevents the sensors from being affected, clogging or other faults when measuring the concentration of the disinfectant, especially if the measurement works according to the flow principle.

Another alternative or additional embodiment of the method provides, before the start of post-disinfection of the treatment liquid, to add an amount of disinfectant that corresponds to the minimum concentration of disinfectant in the treatment liquid, preferably at the end of the wash, in particular the main wash, or is higher by a certain percentage. This contributes to an adequate 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 final wash. In particular, the sample is also used for this measurement, with which at least one sensor determines the concentration of the disinfectant in the treatment liquid. 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 finding 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 with target values can be obtained. This ensures a high level of accuracy, reliability and significance of the data 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 Durchlaufwaschmaschine aufweisenden Vorrichtung zur Durchführung des Verfahrens, und

Fig. 2

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

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

1

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

2

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

The following description relates to the disinfection of laundry during the wet treatment thereof in a tunnel 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 textiles of all kinds that need to be disinfected, in particular items of clothing, work clothing, flat linen, but also dust control mats or the like.

The one in the 1 The continuous washing machine 10 shown schematically in a side view has a drum 12 that can be driven to rotate or pivot (back and forth) about a preferably horizontal axis of rotation 11. The axis of rotation 11 runs centrally through the drum 12, preferably horizontally. The laundry is transported batch by batch in the direction of passage 13 through the cylindrical drum 12 which is driven in a rotating or pivoting manner.

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

The one in the 1 The continuous washing machine 10 shown has three treatment zones that follow one another in the direction of flow 13 . 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 size. The treatment zones are a prewash zone 16, a final wash zone 17 that follows in the flow direction 13, and a rinsing zone 18 behind the final wash zone 17. In the tunnel washing machine 10 described here, the laundry is simultaneously disinfected in the final wash zone 17 during the final wash. An after-treatment zone, for example a finishing zone and/or neutralization zone, can be integrated into the rinsing zone 18 .

On the continuous washing machine 10 follows in the 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, after-treatment of the pre-washed, clear-washed and disinfected laundry. Then the tunnel washing machine 10 does not need to have a rinsing zone 18 .

The drum 12 of the tunnel washing machine 10 is assigned a plurality of stationary and liquid-impermeable outer drums. A first outer drum 19 viewed in the throughput direction 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 . A third outer drum 21 is provided at the end of the main wash zone 17 . 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. 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 liquid-impermeable.

A loading chute 24 is located in front of the drum 12, with which the tunnel washing machine 10 is loaded in batches by the dirty and possibly also contaminated laundry entering the first chamber 15 of the prewash zone 16 of the tunnel washing machine 10 via the loading chute 24. A discharge chute 25 is provided at the end of the tunnel washing machine 10 . About the discharge chute 25 leaves the washed, disinfected and optionally rinsed laundry lot by batch the last chamber 15 of the continuous washing machine 10. From the discharge chute 25, the wet-treated laundry items with it still bound liquid, the so-called bound liquor, the dewatering device, not shown, are supplied.

In the tunnel washing machine 10 shown, a sampling line 26 branches off from the second outer drum 20 at the start 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 zone 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 alternately one sampling line 26 or 27 can be temporarily opened. The ends of the sampling lines 26 and 27 located behind the shut-off valves 28 and 29 meet at a collection point 30, from there with a common, in particular single, through-flow line 34 to a pump 31, from there through at least one filter 32 and from the filter 32 to be transported to a flow meter 33 .

At the in the 1 shown embodiment, it is possible to take samples of the treatment liquid with at least one of these metered disinfectants through the sampling line 26 and 27 before and/or at the beginning of the main wash zone 17 and at the end or behind the main wash zone 17. Alternative designs of the tunnel 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 1 The concentration of the disinfectant in the treatment liquid cannot be measured at the start and end of the main wash zone 17, but either the concentration of the disinfectant in the treatment liquid before or at the start of the main wash zone 17 or at the end or behind the main wash zone 17.

The 2 shows the flow measuring device 33 in more detail in connection with a cross section through the drum 12 of the tunnel washing machine 10 in the area of the third outer drum 21 behind or at the end of the main wash zone 17. Here the sample coming from the sampling line 26 when the shut-off valve 28 is open flows to a small enough sample for analysis 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 get to the pump 31. The pump 31 conveys the sample containing the disinfectant to be measured through the flow measuring device 33.

In the 2 an exemplary 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 used as a sample with the mixed disinfectant contained therein of the sample and during the measurement the remainder of the sample flows through the respective flow cell 37, 38. 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 measuring value recorders, preferably those which are designed as sensors, namely a conductance sensor 39, a temperature sensor 40 and a pH value sensor. sensor 41

At least one sensor for a specific disinfectant is assigned to the second flow cell 38 following the flow cell 37 in the flow direction of the sample. If the disinfectant is peracetic acid, the sensor is designed to measure the concentration of peracetic acid in the sample of 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 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 of the same 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 respective disinfectant used.

In the embodiment of 2 a pH value sensor 43 and/or temperature sensor 44 is 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 a pH value sensor 41, 43 to only the flow cell 37 or the flow cell 38. The conductivity sensor 39, the temperature sensor 40, 44 and/or the pH value sensor 41, 43 can also be provided at least simply at a different point in the tunnel washing machine 10. No temperature sensors 40, 44, pH value sensors 41, 43 and/or conductance sensors 39 are then assigned to the flow cells 37 and 38.

In the embodiment of 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 before the first flow cell 37 . It is also conceivable to provide a mixer 45 in front of each flow cell 37 and 38, optionally also different types of mixers.

Furthermore, the 2 It can be seen that two drains are provided behind the second flow cell 38, namely a drain 46 for draining the sample into a sewer and a drain 47 for returning the sample to that chamber 15 of the tunnel washing machine 10 that has the third outer drum 21 behind the main wash zone 17 is assigned. Both drains 46 and 47 are provided with a shut-off valve 48, 49 for selectively shutting off or releasing the respective drain 46, 47.

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

In the embodiment of 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, the sample between the two flow-through cells 37, 38 can be supplied with fresh water in a targeted quantity if required. This can happen, for example, if the temperature sensor 40 of the first flow cell 37 detects that the temperature of the sample is too high, which should preferably be between 30° and 40°, in particular 32° to 38°. Then the high temperature can be reduced to the specified or optimal temperature by supplying an appropriate amount of fresh water when from Temperature sensor 40 of the first flow cell 37 too high a temperature of the sample is detected. The temperature sensor 44 of the downstream flow cell 38 then measures the cooled sample resulting from the addition of cold fresh water to determine whether the temperature of the sample after the dosed addition of fresh water is at the temperature intended and/or the optimum temperature for measuring the concentration of the disinfectant in the sample.

The one in the 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, in the 2 The flow measuring device 33 shown in connection with the third outer drum 21 behind the main wash zone 17 with its additional components can also be provided in the area of the second outer drum 20 before the main wash zone 17 . Then the concentration of the disinfectant in the treatment liquid is also (additionally) determined before the main wash, which makes it possible to determine whether the treatment liquid contains enough disinfectant for adequate disinfection of the laundry. If this is not the case, the concentration of at least one disinfectant in the treatment liquid can be increased to the intended target concentration before the main wash by adding at least one disinfectant.

If, as shown in the 1 is measured by the single flow meter 33 both the concentration of the disinfectant before and after the main wash zone 17 is in the 2 A sample from the area of the second outer drum 20 in front of the main wash zone 17 can also be supplied. Then, as shown in the 2 before the filter 32 in the 1 Collection point 30 shown, on the optional at least one sample from the second outer drum 20 before the main wash zone 17 or the third outer drum 21 behind the main wash zone 17 to the only one in the 2 shown flow measuring device 33 and its additional components can be supplied by actuating the shut-off valve 28, 29 in the sampling lines 26 or 27 accordingly.

The filter 32 is designed in such a way that it has a filter quality that ensures that measurement results can be determined by the sensors in the flow cells 37, 38 that cannot be impaired by components in the sample that are to be filtered out. The filter 32 is preferably a fine filter, in particular an ultra-fine filter with at least one filter membrane. Alternatively, it is also conceivable instead of a filter 32 to provide several consecutive 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 superfine filter, are then provided.

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

According to the invention, the method is designed such that a check is carried out to determine whether the laundry has been disinfected 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 after the washing process, in particular after the main wash. In this way, the completeness of the disinfection is checked "in situ". This makes it possible--if necessary due to the measurement--to extend the disinfection process beyond the intended time period by a certain empirically determined and/or calculated time period.

Although it is preferred to check the disinfection process after the main wash, it is also conceivable to check the completeness of the disinfection during other phases of the washing process. It is also conceivable to check the completeness of the disinfection when rinsing the washed laundry and/or during an after-treatment of the laundry, 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 tunnel 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 quantity of treatment liquid, namely main wash liquid, with the remainder that is ideally still present therein, is discharged Disinfectant taken as a sample. The volume of this sample is only as large as required for the automatic measurement of the residual proportion of disinfectants in the treatment liquid. For example, a few liters of the treatment liquid, namely the main wash liquid, with the residual disinfectant still present in it are sufficient as a sample to be measured.

After the sample has been filtered in 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. In addition or as an alternative, the conductance sensor 39 can also measure the conductance of the sample, ie 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, the measured temperature and/or the pH value can be used to compensate and/or correct measured values. This prevents the measured value of the concentration measured in the following second flow cell 38 or in particular the residual concentration after disinfection of the disinfectant at different temperatures and/or pH values in the sample from being falsified and thus meaningful measured values for the after disinfection in the treatment liquid any remaining disinfectants are present. If the conductance of the treatment liquid with the disinfectant still present in it is determined by the conductance sensor 39 in the first flow cell 37, this can further improve the measurement result, particularly with certain disinfectants.

The sample leaving the first flow cell 37 is mixed again in the mixer 45 in order to bring about an even 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.

As in the first flow cell 37, the second flow cell 38 preferably continuously measures at least the concentration of the remaining at least one disinfectant in the treatment liquid or the final wash liquid as the sample flows through. This is done with at least one disinfectant sensor matched to the respective disinfectant. This is about 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 if different disinfectants are to be measured.

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

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 that the laundry has been adequately disinfected, in particular 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 security of complete disinfection. Then the at least one disinfectant sensor 42 determines the concentration of the disinfectant in the treatment liquid at the end of the main wash zone and compares it with the specified minimum residual concentration.

If the above-described check of the completeness of the disinfection shows that after the disinfection process there is no more disinfectant in the treatment liquid or 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 found to be too low, the disinfection duration can be extended by prolonging the disinfection of the laundry or post-disinfecting with the remaining disinfectant until the laundry is completely disinfected. However, if no more disinfectant 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 post-dosed 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 a different location on the drum 12 of the tunnel washing machine 10, in particular on at least one other outer drum 19, 20, 22 and/or 23 .

In the representation of 1 provision is also made before the main wash, i.e. at the start of main wash zone 17, to branch off a sample of the treatment liquid, in particular main wash liquid, with at least one disinfectant added to it from the second outer drum 20 assigned to it and via the sample removal line 26 and the collection point 30 away from 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 to transport. The measurement of the concentration of the at least one disinfectant in the as yet unused main wash liquid takes place here in exactly the same way as described in connection with the measurement of the concentration of the remaining disinfectant in the used treatment liquid, in particular main wash liquid. Only the concentration of the at least one disinfectant in the unused treatment liquid is measured before the disinfection in front of 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 at least one disinfectant is added in the missing quantity before the start of the main wash and thus also the disinfection process. The disinfection process can then begin, if necessary after a renewed measurement of the concentration of the at least one disinfectant in the treatment liquid, in particular the main wash liquid.

The method according to the invention was described below in connection with a tunnel washing machine 10 for commercial laundries. In principle, however, the method can also be used in connection with other washing machines, in particular washer-extractors, specifically those that are also used in commercial laundries. <b>List of reference characters:</b> 10 tunnel washing machine 42 Disinfectant Sensor 11 axis of rotation 43 pH sensor 12 drum 44 temperature sensor 13 flow direction 45 mixer 14 partition wall 46 drain 15 chamber 47 drain 16 prewash zone 48 shut-off valve 17 main wash zone 49 shut-off valve 18 rinsing zone 50 flow meter 19 first outer drum 51 fresh water inlet 20 second outer drum 52 dosing pump 21 third outer drum 53 shut-off valve 22 fourth outer drum 23 fifth outer drum 24 loading chute 25 discharge chute 26 sampling line 27 sampling line 28 shut-off valve 29 shut-off valve 30 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 conductance sensor 40 temperature sensor 41 pH sensor

Claims (8)

1. 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, and the disinfectant is measured after the disinfection or before and after the disinfection, characterized in that, with at least one sensor for a respective specific disinfectant, the concentration of the respective disinfectant in the treatment liquid is measured, in that various sensors for different disinfectants, according to the type of laundry, are provided and specifically measure the concentration in the treatment liquid of the respective disinfectant used and, when there is too low a concentration of the at least one disinfectant in the treatment liquid measured after washing, the washing is continued beyond the post-disinfection time period.
2. Method according to Claim 1, characterized in that a pre-washing is performed in a treatment liquid serving for the purpose, in particular a pre-washing liquid, and the final washing is performed in another treatment liquid serving for the purpose, in particular a final washing liquid, wherein the laundry is disinfected in the final washing and at least one disinfectant is thereby added to the treatment liquid serving for the final washing.
3. Method according to one of the preceding claims, characterized in that the concentration of the at least one disinfectant is measured by at least one sensor on the basis of the flow principle, in particular with a fixed constant temperature.
4. Method according to one of the preceding claims, characterized in that, before and/or after the disinfection of the laundry, a small amount, sufficient for measuring the concentration of the at least one disinfectant in the treatment liquid, is diverted as a sample of the treatment liquid comprising the disinfectant from the overall treatment liquid serving for the washing, preferably final washing, with the disinfectant still present in it.
5. Method according to Claim 4, characterized in that the diverted sample of a small amount of the treatment liquid comprising the disinfectant is first filtered at least once before it is passed to the at least one sensor.
6. Method according to one of the preceding claims, characterized in that, in the case of too low a concentration of the at least one disinfectant in the treatment liquid measured after the final washing, the final washing is continued beyond a post-disinfection time period.
7. Method according to Claim 1, characterized in that, before the beginning of the post-disinfection, such an amount of disinfectant that corresponds to the minimum concentration of the at least one disinfectant in the treatment liquid at the end of the washing, preferably final washing, and/or the end of the disinfection operation is added to the treatment liquid.
8. Method according to one of the preceding claims, characterized in that, at least before and/or after the washing, preferably after the final washing, the pH of the treatment liquid with the at least one disinfectant possibly still present in it is measured, in particular the sample is also used for this measurement.

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