Conveyor dishwasher having a sensor device for detecting the concentration of disinfectant

Abstract

The present invention relates to a conveyor dishwasherwith at least one final rinse zone with at least one final rinse nozzle for spraying final rinse liquid onto washware, and wherein a metering device associated with the final rinse zone is provided for adding a disinfectant to the final rinse liquid in a metered manner. A sensor device is configured to detect the concentration of disinfectant in the final rinse liquid which is sprayed in the final rinse zone. Furthermore, a control device is configured to compare the value of the concentration of disinfectant which is detected by the sensor device with predefinable concentration values and, in the event of excessively high deviations of the concentration of disinfectant from the predefinable concentration values, to interrupt the dishwashing process or to output a warning signal to an operator.

Claims

1. A conveyor dishwasher for washing washware, wherein the conveyor dishwasher has at least one wash zone with at least one wash nozzle for spraying wash liquid onto the washware, and has at least one final rinse zone with at least one final rinse nozzle for spraying final rinse liquid onto the washware, and wherein a metering device is connected for adding a disinfectant to a final rinse line that feeds the at least one final rinse nozzle so that the disinfectant is added to the final rinse liquid in a metered manner prior to spraying of the final rinse liquid from the at least one final rinse nozzle, characterized in that a sensor device is provided, the sensor device being configured to detect a concentration of disinfectant in the final rinse liquid in the final rinse line prior to spraying of the final rinse liquid from the at least one final rinse nozzle in the final rinse zone, and in that a control device is provided, the control device being configured to compare the value of the concentration of disinfectant which is detected by the sensor device with a predefined concentration value and, in the event the concentration of disinfectant deviates by at least a defined deviation value from the predefined concentration value, to interrupt the dishwashing process or to output a warning signal to an operator.

2. The conveyor dishwasher as claimed in claim 1, wherein the control device is configured in such a way that the defined deviation value can be adjusted.

3. The conveyor dishwasher as claimed in claim 2, wherein the defined deviation value is a first defined deviation value, wherein the control device is configured such that if the concentration of disinfectant which is measured by the sensor device deviates above the predefined concentration value by at least the first defined deviation value, or if the concentration of disinfectant which is measured by the sensor device deviates below the first predefined concentration value by at least a second defined deviation value, the control device interrupts the dishwashing process or outputs the warning signal to an operator, wherein the second defined deviation value is different than the first defined deviation value.

4. The conveyor dishwasher as claimed in claim 2 wherein the conveyor dishwasher has a conveyor apparatus for conveying washware through the at least one wash zone and the at least one final rinse zone, and wherein the control device is configured to stop the conveyor apparatus as soon as the concentration of disinfectant deviates by at least the defined deviation value from the predefined concentration value.

5. The conveyor dishwasher as claimed in claim 2, wherein the control device is configured to interrupt the spraying of wash liquid and/or final rinse liquid as soon as the concentration of disinfectant deviates by at least the defined deviation value from the predefined concentration value.

6. The conveyor dishwasher as claimed in claim 2, wherein the control device is configured to output an optical or acoustic warning signal as soon as the concentration of disinfectant deviates by at least the defined deviation value from the predefined concentration value.

7. The conveyor dishwasher as claimed in claim 6, wherein the control device is configured to output causes for the concentration of disinfectant deviating by at least the defined deviation value from the predefined concentration value, together with the optical or acoustic warning signal.

8. The conveyor dishwasher as claimed in claim 1, wherein the control device is configured to interrupt the dishwashing process or to output a warning signal to an operator as soon as a concentration of disinfectant falls below 50 ppm and/or as soon as a concentration of disinfectant rises above 100 ppm.

9. The conveyor dishwasher as claimed in claim 1, wherein the metered disinfectant contains a chlorine solution.

10. The conveyor dishwasher as claimed in claim 9, wherein the sensor device is configured to detect free chlorine radicals.

11. The conveyor dishwasher as claimed in claim 10, wherein the sensor device is configured to detect free chlorine radicals in a concentration range of between 0 and 200 ppm.

12. The conveyor dishwasher as claimed in claim 10, wherein the sensor device is configured to detect free chlorine radicals with a measurement resolution of no worse than 5 ppm.

13. The conveyor dishwasher as claimed in claim 1, wherein the sensor device is configured to detect the concentration of disinfectant continuously or at predefinable time intervals.

14. The conveyor dishwasher as claimed in claim 1, wherein the liquid which is sprayed in the at least one wash zone has a temperature of less than 60 C., and/or wherein the liquid which is sprayed in the at least one final rinse zone has a temperature of less than 80 C.

15. The conveyor dishwasher as claimed in claim 1, wherein the conveyor dishwasher further has at least one pre-rinse zone with at least one pre-rinse nozzle, which pre-rinse zone is arranged upstream of the final rinse zone, wherein a metering device is connected for adding a disinfectant to a pre-rinse line that feeds the at least one pre-rinse nozzle so that disinfectant is added to the pre-rinse liquid in a metered manner prior to spraying of the pr-rinse liquid from the at least one pre-rinse nozzle, and wherein the sensor device is further configured to detect the concentration of disinfectant in the pre-rinse liquid in the pre-rinse line prior to spraying of the pre-rinse liquid from the at least one pre-rinse nozzle in the pre-rinse zone.

16. The conveyor dishwasher as claimed in claim 15, wherein at least a portion of the final rinse liquid which is sprayed in the final rinse zone is reused as pre-rinse liquid.

17. A conveyor dishwasher for washing washware, wherein the conveyor dishwasher has at least one wash zone with at least one wash nozzle for spraying wash liquid onto the washware, and has at least one final rinse zone with at least one final rinse nozzle for spraying final rinse liquid onto the washware, and wherein a metering device is connected for adding a disinfectant to final rinse liquid that is fed to the at least one final rinse nozzle so that the disinfectant is added to the final rinse liquid in a metered manner prior to spraying of the final rinse liquid from the at least one final rinse nozzle, wherein a sensor device is configured to detect a concentration of disinfectant in the final rinse liquid prior to spraying of the final rinse liquid from the at least one final rinse nozzle in the final rinse zone, and a control device is configured to compare the value of the concentration of disinfectant which is detected by the sensor device with a predefined concentration value and, in the event the concentration of disinfectant deviates by at least a first defined deviation value above the predefined concentration value or by at least a second defined deviation value below the predefined concentration value, to interrupt the dishwashing process or to output a warning signal to an operator, wherein the second defined deviation value is different than the first defined deviation value.

Description

(1) In the text which follows, the invention will be described in greater detail with reference to the exemplary embodiment of the conveyor dishwasher according to the invention illustrated in the drawing, in which:

(2) FIG. 1: shows a schematic side view of a conveyor dishwasher according to a first embodiment of the invention.

(3) FIG. 1 shows a schematic side view of a conveyor dishwasher 1 according to a first embodiment of the invention having a conveyor apparatus 2 for conveying washware, not illustrated, in a conveying direction T through the conveyor dishwasher 1. The conveyor dishwasher 1 has at least one wash zone, as illustrated in FIG. 1 for example, a pre-wash zone 10 and three main-wash zones 11.1, 11.2, 11.3 which are arranged downstream of the pre-wash zone 10 as seen in the conveying direction T.

(4) As seen in the conveying direction T, a post-wash zone or pre-rinse zone 12 is arranged downstream of the at least one wash zone 10, 11.1, 11.2, 11.3, and at least one final rinse zone, for example only a first final rinse zone 13.1 as illustrated, in which final rinse liquid containing a metered disinfection chemical is sprayed onto the washware, and a second additional final rinse zone or post-disinfection final rinse zone 13.2, in which fresh water without a metered disinfection chemical is sprayed onto the washware continuously or as required, are arranged downstream of the post-wash zone or pre-rinse zone 12. In the conveyor dishwasher 1 illustrated in FIG. 1, the additional final rinse zone or post-disinfection final rinse zone 13.2 is followed by a drying zone 14 as seen in the conveying direction T of the washware.

(5) The respective zones 10, 11.1, 11.2, 11.3, 12, 13.1, 13.2 and 14 of the conveyor dishwasher 1 can be separated from one another by means of separating curtains 5. In the embodiment illustrated in FIG. 1, the inlet tunnel 3 of the conveyor dishwasher 1 itself is also separated from the machine inlet 4 by a separating curtain 5. The provision of the separating curtains 5 prevents wash liquid and final rinse liquid spraying between zones and prevents vapors escaping from the conveyor dishwasher 1.

(6) Said treatment zones 10, 11.1, 11.2, 11.3, 12, 13.1 and 13.2 of the conveyor dishwasher 1 have associated spray nozzles 30a, 30b, 31.1a, 31.1b, 31.2a, 31.2b, 31.3a, 31.3b, 32a, 32b, 33a, 33b, 34a and 34b. These spray nozzles 30a, 30b, 31.1a, 31.1b, 31.2a, 31.2b, 31.3a, 31.3b, 32a, 32b, 33a, 33b, 34a and 34b serve to spray liquid onto the washware to be treated as said washware is conveyed through the respective treatment zones 10, 11.1, 11.2, 11.3, 12, 13.1 and 13.2 by the conveyor apparatus 2. The individual spray systems of the treatment zones 10, 11.1, 11.2, 11.3, 12, 13.1 and 13.2 ensure that the washware to be treated is sprayed down both from the top and from the bottom. It would also be feasible to additionally further provide lateral spray nozzles.

(7) The main-wash zones 11.1, 11.2, 11.3 and the pre-wash zone 10 further have associated tanks (main-wash tanks 21.1, 21.2, 21.3, pre-wash tank 20) for accommodating sprayed liquid and/or for providing liquid for the spray nozzles 30a, 30b, 31.1a, 31.1b, 31.2a, 31.2b, 31.3a and 31.3b of the relevant treatment zones 10, 11.1, 11.2, 11.3 and 12.

(8) The additional final rinse zone or post-disinfection final rinse zone 13.2 has an associated collection device 22.2 for collecting liquid which is sprayed in the additional final rinse zone 13.2. As illustrated, the collection device 22.2 which is associated with the additional final rinse zone 13.2 can be in the form of a tank or in the form of a collection container, wherein the intention is for this collection device 22.2 to be arranged with respect to the spray nozzles (final rinse nozzles) 34a, 34b which are associated with the additional final rinse zone 13.2 in such a way that the liquid which is sprayed in the additional final rinse zone 13.2 flows into the collection device 22.2 due to the force of gravity and is collected there.

(9) In the illustrated embodiment, the final rinse zone 13.1 which is arranged upstream of the additional final rinse zone or post-disinfection final rinse zone 13.2 likewise has an associated collection devicein this case in the form of a tankwhich is denoted by the reference numeral 22.1 in FIG. 1. Said collection device 22.1 which is associated with the final rinse zone 13.1 is formed separately from the collection device 22.2 which is associated with the additional final rinse zone 13.2 and therefore serves to collect the liquid which is sprayed in the final rinse zone 13.1. The liquid which is collected in the collection device 22.1 which is associated with the final rinse zone 13.1 is supplied to the spray nozzles 32a, 32b which are associated with the pre-rinse zone 12 with the aid of a pump (pre-rinse pump 38b).

(10) In the conveyor dishwasher 1 which is illustrated in FIG. 1, final rinse liquid, which is made up of fresh water with a rinse aid which may be added in a metered manner and is of equal quality to drinking water in microbiological terms, is sprayed in the additional final rinse zone or post-disinfection final rinse zone 13.2 onto the washware, not illustrated, by means of the final rinse nozzles 34a, 34b which are arranged above and below the conveyor apparatus 2 and optionally also to the sides of said conveyor apparatus. The final rinse liquid which is sprayed in the additional final rinse zone or post-disinfection final rinse zone 13.2 is collected in the collection device 22.2 which is associated with the additional final rinse zone or post-disinfection final rinse zone 13.2 and, in particular, does not enter the final rinse zone 13.1 which is arranged upstream of the additional final rinse zone or post-disinfection final rinse zone 13.2.

(11) In the final rinse zone 13.1 however, final rinse liquid, which is made up of fresh water with metered disinfection chemical and possibly metered rinse aid, is sprayed onto the washware, not illustrated, by means of the final rinse nozzles 33a, 33b which are arranged above and below the conveyor apparatus 2 and optionally also to the sides of said conveyor apparatus. The liquid which is sprayed in the final rinse zone 13.1 is collected in the collection device 22.1 which is associated with the final rinse zone 13.1 and is then supplied to the pre-rinse nozzles 32a, 32b of the pre-rinse zone 12 with the aid of the pre-rinse pump 38b. Wash liquid is rinsed off from the washware in the pre-rinse zone 12. The liquid (pre-rinse liquid) which is sprayed onto the washware, not illustrated, by the pre-rinse nozzles 32a, 32b in the pre-rinse zone 12 is conveyed from treatment zone to treatment zone by means of a cascade system in the opposite direction to the conveying direction T of the washware. However, it would also be feasible here for only a portion of the liquid which is sprayed in the pre-rinse zone 12 to be conveyed by means of the cascade system in the opposite direction to the conveying direction T, while the remaining portion of the pre-rinse liquid which is sprayed in the pre-rinse zone 12 is conducted directly into the pre-wash tank 20, which is associated with the pre-wash zone 10, via a valve (not illustrated) and a bypass line (not illustrated).

(12) In the cascade system, the pre-rinse liquid which is sprayed by the pre-rinse nozzles 32a, 32b flows from the pre-rinse zone 12 into the main-wash tank 21.1 which is associated with the (main-) wash zone 11.1 due to the force of gravity. The pre-rinse liquid which is sprayed in the pre-rinse zone 12 and collected by the main-wash tank 21.1 is then delivered to the spray nozzles of the (main-) wash zone 11.1 (upper and lower main-wash nozzles 31.1a, 31.1b) with the aid of a main-wash pump 35.1.

(13) In the conveyor dishwasher 1 which is illustrated in the drawings, the final rinse zone 13.1 and the additional final rinse zone 13.2 are supplied with fresh water, wherein the fresh water supply is divided. A disinfection chemical, for example NaOCl, is metered via a metering pump 50 in the final rinse liquid line 41 into a first portion of the fresh water which is supplied to the conveyor dishwasher 1. It goes without saying that other disinfection chemicals, for example chlorine dioxide (ClO2) or sodium hypochloride (NaOCl) or hypochlorous acid (HClO) can also be added in a metered manner depending on requirements. The fresh water to which the disinfection chemical is admixed serves, in the final rinse zone 13.1, as a final rinse liquid with a disinfection action which is discharged by means of the final rinse nozzles 33a and 33b which are associated with the final rinse zone 13.1.

(14) A disinfection chemical is deliberately not admixed with the second portion of the fresh water which is supplied to the conveyor dishwasher 1 since this portion serves for post-disinfection final rinsing in the additional final rinse zone 13.2 and is sprayed by means of the final rinse nozzles 34a and 34b which are associated with the additional final rinse zone 13.2.

(15) In the embodiment which is illustrated in FIG. 1, the temperature of the liquid which is sprayed in the additional final rinse zone 13.2 is at least substantially identical to the temperature of the liquid which is sprayed in the final rinse zone 13.1. The quantity of final rinse liquid which is introduced into the final rinse zone 13.1 per unit time can be adjusted via a valve V3.

(16) In the embodiment which is illustrated in FIG. 1, the liquid which is collected in the collection device 22.2 of the post-disinfection final rinse zone or additional final rinse zone 13.2 is supplied cyclically to the last main-wash zone 11.1 which immediately adjoins the pre-rinse zone 12, and in particular to the main-wash tank 21.1 which is associated with the main-wash zone 11.1, by means of a liquid transfer system comprising a pump 38a and a bypass line 6. However, as an alternative to this, it would be also feasible for the liquid which is collected in the collection device 22.2 to be pumped out of the collection device 22.2, which is in the form of a tank, in a manner controlled with respect to time or level.

(17) The final rinse liquid into which the disinfection chemical has been metered is collected in the collection device 22.1, which is likewise in the form of a tank, after being sprayed by means of the final rinse nozzles 33a and 33b which are associated with the final rinse zone 13.1, and then serves as a pre-rinse liquid in the pre-rinse zone 12. To this end, a pump 38b is provided, this pump pumping the liquid which is sprayed in the final rinse zone 13.1 and collected in the collection device 22.1 out of the collection device 22.1 which is in the form of a tank, and supplying said liquid to the pre-rinse nozzles 32a and 32b via a pre-rinse liquid line 42.

(18) In the embodiment which is illustrated in FIG. 1, provision is made for it to be possible for the disinfection chemical (here: NaOCl) to be metered both into the final rinse liquid which is to be sprayed in the final rinse zone 13.1 and also into the pre-rinse liquid which is to be sprayed in the pre-rinse zone 12. To this end, a first metering device (metering pump 50), which is associated with the final rinse zone 13.1, and a second metering device (metering pump 51), which is formed and can be actuated independently of said first metering device, are provided, wherein the second metering device (metering pump 51) is associated with the pre-rinse zone 12. Specifically, the first metering pump 50 is connected or can be connected to the final rinse line 41 for this purpose, whereas the second metering pump 51 is connected or can be connected to the pre-rinse line 42.

(19) In both cases, the corresponding metering device (metering pump 50, 51) is adjusted or actuated in such a way that the final rinse liquid which is sprayed in the final rinse zone 13.1 and the pre-rinse liquid which is sprayed in the pre-rinse zone 12 have a predefinable or predefined minimum concentration of disinfection chemical which depends on the type of metered disinfection chemical. To this end, the metering devices (metering pumps 50, 51) are connected or can be connected firstly to the control device 100 and secondly to the disinfectant containers 60, 61. As already indicated, a minimum concentration of 50 ppm is required when sodium hypochlorite (NaOCl) is used as the disinfection chemical.

(20) Wash liquid is rinsed off from the washware in the pre-rinse zone 12. The liquid produced in the process flows into the main-wash tank 21.1, which is associated with the first main-wash zone 11.1, due to the force of gravity. A discharge element 7, for example a discharge base or a baffle plate, which conducts the pre-rinse liquid which is sprayed by the pre-rinse nozzles 32a, 32b into the main-wash tank 21.1 is preferably provided for this purpose. According to another embodiment, not illustrated, of the conveyor dishwasher 1, the discharge element 7 can be dispensed with if the main-wash tank 21.1 extends as far as beneath the pre-rinse nozzles 32a, 32b of the pre-rinse zone 12.

(21) The liquid which is accommodated in the main-wash tank 21.1 of the first main-wash zone 11.1 is usually provided with a detergent and sprayed onto the washware by means of the spray nozzles of the first main-wash zone 11.1 (upper and lower main-wash nozzles 31.1a, 31.1b) with the aid of a first main-wash pump 35.1. The wash liquid which is sprayed by the main-wash nozzles 31.1a, 31.1b then flows back into the main-wash tank 21.1 due to the force of gravity.

(22) The main-wash tank 21.1 is fluidically connected to the main-wash tank 21.2 which is associated with the second main-wash zone 11.2 via an overflow 9.1. The wash liquid which is sprayed in the first main-wash zone 11.1 enters the main-wash tank 21.2 of the second main-wash zone 11.2 via this overflow 9.1 when there is a sufficient quantity of wash liquid in the main-wash tank 21.1 of the first main-wash zone 11.1.

(23) The liquid which is accommodated in the main-wash tank 21.2 of the second main-wash zone 11.2 is sprayed onto the washware by means of the spray nozzles of the second main-wash zone 11.2 (upper and lower main-wash nozzles 31.2a, 31.2b) with the aid of second main-wash pumps 35.2. The wash liquid which is sprayed by the main-wash nozzles 31.2a, 31.2b then flows back into the main-wash tank 21.2 of the second main-wash zone 11.2 due to the force of gravity.

(24) The main-wash tank 21.2 of the second main-wash zone 11.2 is fluidically connected to the pre-wash tank 20 which is associated with the pre-wash zone 10 via an overflow line 9.2. The wash liquid which is sprayed in the second main-wash zone 11.2 enters the main-wash tank 21.3 via this overflow line 9.2 when there is a sufficient quantity of wash liquid in the main-wash tank 21.2 of the second main-wash zone 11.2.

(25) The liquid which is accommodated in the main-wash tank 21.3 of the third main-wash zone 11.3 is sprayed onto the washware by means of the spray nozzles of the third main-wash zone 11.3 (upper and lower main-wash nozzles 31.3a, 31.3b) with the aid of third main-wash pumps 35.3. The wash liquid which is sprayed by the main-wash nozzles 31.3a, 31.3b then flows back into the main-wash tank 21.3 of the third main-wash zone 11.3 due to the force of gravity.

(26) The main-wash tank 21.3 of the third main-wash zone 11.3 is fluidically connected to the pre-wash tank 20 which is associated with the pre-wash zone 10 via an overflow line 9.3. The wash liquid which is sprayed in the third main-wash zone 11.3 enters the pre-wash tank 20 via this overflow line 9.3 when there is a sufficient quantity of wash liquid in the main-wash tank 21.3 of the third main-wash zone 11.3.

(27) The liquid which is accommodated in the pre-wash tank 20 of the pre-wash zone 10 is then sprayed onto the washware by means of the spray nozzles of the pre-wash zone 10 (upper and lower pre-wash nozzles 30a, 30b) with the aid of pre-wash pumps 34 in order to remove coarse particles of dirt from the washware. The wash liquid which is sprayed by the pre-wash nozzles 30a, 30b then flows back into the pre-wash tank 20 due to the force of gravity.

(28) As already indicated, the liquid which is sprayed in the main-wash zones 11.1, 11.2 and 11.3 in the pre-wash zone 10 preferably contains detergent which is added in a metered fashion with the aid of a detergent metering apparatus (not shown in the drawings), for example, to the liquid which is accommodated in the main-wash tank 21.1 of the first main-wash zone 11.1.

(29) The additional final rinse zone or post-disinfection final rinse zone 13.2 is followed by the abovementioned drying zone 14 in the conveying direction T. In the drying zone 14, the washware is dried using dry and heated air in order to blow off and/or dry up the moisture on the washware. In order to keep the moisture content of the air in a range which is expedient for drying, it is feasible, for example, to supply ambient air to the drying zone 14 from outside via an opening, for example through the outlet opening for the washware.

(30) The warm and moisture-laden air in the drying zone 14 is then drawn-off from the drying zone 14 via a further opening, for example with the aid of a fan 15. It is advantageous here when the exhaust air stream from the drying zone 14 passes a heat-recovery device 16 in which, for example, a condenser can be provided. The heat-recovery device 16 serves to recover at least some of the thermal energy contained in the exhaust air. This recovered thermal energy can be used, for example, to heat the liquid which is sprayed in the final rinse zones 13.1 and 13.2.

(31) The final rinse zones 13.1, 13.2 can have an associated common fresh water container 23 in order to temporarily store at least a portion of the fresh water which is provided for final rinsing (disinfection final rinsing and post-disinfection final rinsing). The fresh water container 23 is firstly provided with a fresh water connection which can be connected to a fresh water supply system via an actuable fresh water feed valve V1. Secondly, the fresh water container 23 is connected to the intake end of a first final rinse pump 37a.

(32) The delivery end of the first final rinse pump 37a is connected to the upstream end region of a first line system 40, by means of which first line system fresh water is delivered from the fresh water container 23 to the final rinse nozzles 33a, 33b, 34a and 34b when the first final rinse pump 37a is operated. Specifically, the first line system 40 connects the delivery end of the first final rinse pump 37a to a throughflow heater 17.1 (boiler). In this case, the first line system 40 is formed in such a way that the liquid which is supplied from the first final rinse pump 37a to the final rinse nozzles 33a, 33b, 33a and 34b first passes the heat-recovery device 16 before reaching the throughflow heater 17.1. In this way, it is possible to use at least some of the thermal energy from the exhaust air which is discharged from the drying zone 14 to heat the liquid which is supplied to the spray nozzles 33a, 33b, 34a and 34b by means of the first line system 40. The fresh water which is supplied by means of the first line system 40 is therefore correspondingly heated.

(33) A second line system, what is called the pre-rinse liquid line 42, connects the collection device 22.1, which is in the form of a tank and is associated with the final rinse zone 13.1, to the pre-rinse nozzles 32a and 32b of the pre-rinse zone 12 by means of a throughflow heater 17.2 (boiler). The temperature of the pre-rinse liquid which is supplied to the pre-rinse nozzles 32a and 32b can therefore be controlled independently of the temperature of the final rinse liquids which are sprayed in the final rinse zone 13.1 and in the additional final rinse zone 13.2. The final rinse temperatures are preferably less than 80 C. and are preferably below 70 C. in this case.

(34) FIG. 1 further shows that a sensor devices 70 is provided in the above-mentioned final rinse liquid line 41. Furthermore, a sensor device 71 can optionally also be provided in the pre-rinse liquid line 42 according to the illustrated embodiment. The sensor devices 70, 71 are each configured to measure the concentration of disinfectant in the final rinse liquid and, respectively, in the pre-rinse liquid. To this end, the two sensor devices 70, 71 are each connected to a control device 100 which is configured to compare the detected value of the concentration of disinfectant with predefinable concentration values. If there are excessively high deviations of the concentration of disinfectant from the predefinable concentration values, the sensor device 100 can interrupt the dishwashing process or output a warning signal to the operator. The warning signals may be, for example, acoustic signals, which are output by means of the loudspeaker 80, or optical signals, which are output by means of a screen 81.

(35) Although not illustrated in FIG. 1, the control device 100 can also be used to stop the conveying device 2 of the conveyor dishwasher 1 if the concentration of disinfectant in the final rinse liquid line 41 or in the pre-rinse liquid line 42 falls below a required minimum concentration or exceeds a required maximum concentration. Specifically, the control device 100 can be connected to a drive of the conveying device 2 for this purpose. As an alternative or in addition, it is feasible for the control device 100 to be connected to the valve V3 in order to interrupt a supply of fresh water to the final rinse liquid line 41 and therefore the supply of final rinse liquid to the final rinse zone 13.1 in the event of excessively high deviations in the concentration of disinfectant. It is also feasible to control the pre-rinse pump 38b by means of the control device 100 in order to interrupt the supply of pre-rinse liquid to the pre-rinse zone as soon as the concentration of disinfectant assumes impermissible values.

(36) The two sensor devices 70, 71 are each arranged directly in the final rinse liquid and, respectively, pre-rinse liquid line 41, 42 according to the embodiment illustrated in FIG. 1. However, as an alternative to this, it is also feasible for said sensor devices to be arranged in a branch line which runs parallel to the final rinse liquid line 41 and, respectively, pre-rinse liquid line 42.

(37) The present invention is not restricted to the exemplary embodiment described above, but rather can be gathered from looking at all the individual features disclosed in said exemplary embodiment together.