Conveyor dishwasher and method for operating a conveyor dishwasher

Patent metadata

Field	Value
Publication number	US-10456007-B2
Application number	US-201515309806-A
Country	US
Kind code	B2
Filing date	May 5, 2015
Priority date	May 9, 2014
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

A conveyor dishwasher (1) has at least one wash zone (11, 12) in which wash liquid is sprayed onto the washware, at least one final rinse zone (14) in which final rinse liquid is sprayed onto the washware and a waste air system (20) for discharging waste air from the conveyor dishwasher (1). To save energy and maintain hygiene performance, a waste water heat recovery system (25) is provided for transferring at least a portion of the thermal energy in the waste water from the conveyor dishwasher (1) as useful heat to the final rinse liquid and a waste air heat recovery system is further provided for transferring at least a portion of the thermal energy in the waste air which is discharged or is to be discharged from the conveyor dishwasher (1) as useful heat to at least the final rinse.

First claim

The invention claimed is:

1. A conveyor dishwasher having a conveying apparatus for conveying washware through individual treatment zones of the conveyor dishwasher, wherein the conveyor dishwasher has at least one wash zone in which wash liquid from a wash tank which is associated with the at least one wash zone is sprayed onto the washware, wherein the conveyor dishwasher further has at least one final rinse zone which is arranged downstream of the at least one wash zone as seen in a conveying direction of the washware and in which final rinse liquid is sprayed onto the washware, and wherein the conveyor dishwasher further has a waste air system for discharging waste air from the conveyor dishwasher,
characterized
in that a waste water heat recovery system is provided for transferring at least a portion of the thermal energy in the waste water from the conveyor dishwasher as heat to the final rinse liquid which is to be sprayed in the at least one final rinse zone, and
in that a waste air heat recovery system is further provided for transferring at least a portion of the thermal energy in the waste air which is discharged or is to be discharged from the conveyor dishwasher as heat to at least the final rinse liquid which is to be sprayed in the at least one final rinse zone.

2. The conveyor dishwasher as claimed in claim 1 ,
wherein the waste water heat recovery system has at least one heat exchanger, which is operated in accordance with the countercurrent principle, for transferring at least a portion of the thermal energy in the waste water as heat to the final rinse liquid which is to be sprayed in the at least one final rinse zone; and
wherein the waste air heat recovery system has at least one heat pump device for transferring at least a portion of the thermal energy in the waste air as heat to at least the final rinse liquid which is to be sprayed in the at least one final rinse zone.

3. The conveyor dishwasher as claimed in claim 2 ,
wherein the heat pump device has at least one evaporator for transferring at least a portion of the thermal energy in the waste air to a refrigerant of the heat pump device; and
wherein the heat pump device further has a first condenser/heat exchanger for transferring at least a portion of the thermal energy in the refrigerant as heat to the final rinse liquid which is to be sprayed in the at least one final rinse zone.

4. The conveyor dishwasher as claimed in claim 3 ,
wherein the at least one heat exchanger of the waste water heat recovery system is arranged upstream of the first condenser/heat exchanger of the heat pump device as seen in the direction of flow of the final rinse liquid which is to be sprayed in the at least one final rinse zone, for preheating the final rinse liquid which is to be sprayed in the final rinse zone.

5. The conveyor dishwasher as claimed in claim 3 ,
wherein the evaporator of the heat pump device is designed to cool the waste air which is discharged or is to be discharged from the conveyor dishwasher to a temperature in a range of between 18° C. and 25° C., in particular to ambient temperature in the room in which the conveyor dishwasher is installed, during operation of the conveyor dishwasher.

6. The conveyor dishwasher as claimed in claim 3 ,
wherein the heat pump device further has a second condenser/heat exchanger which is designed to transfer at least a portion of the thermal energy in the refrigerant as heat to the wash liquid which is to be sprayed in the at least one wash zone of the conveyor dishwasher.

7. The conveyor dishwasher as claimed in claim 6 ,
wherein the second condenser/heat exchanger is arranged upstream of the first condenser/heat exchanger as seen in a direction of flow of the refrigerant.

8. The conveyor dishwasher as claimed in claim 7 ,
wherein a drying zone is further provided, said drying zone being arranged downstream of the at least one final rinse zone as seen in the conveying direction of the washware; and

wherein the heat pump device further has a third condenser/heat exchanger which is designed to transfer at least a portion of the thermal energy in the refrigerant as heat to drying air which is introduced or is to be introduced into the drying zone.

9. The conveyor dishwasher as claimed in claim 8 ,
wherein the third condenser/heat exchanger is arranged upstream of the first condenser/heat exchanger as seen in a direction of flow of the refrigerant.

10. The conveyor dishwasher as claimed in claim 9 ,
wherein a pre-rinse zone is provided, said pre-rinse zone being arranged between the at least one wash zone and the at least one final rinse zone as seen in the conveying direction of the washware; and
wherein the heat pump device further has a fourth condenser/heat exchanger which is designed to transfer at least a portion of the thermal energy in the refrigerant as heat to pre-rinse liquid which is to be sprayed in the pre-rinse zone.

11. The conveyor dishwasher as claimed in claim 10 ,
wherein the fourth condenser/heat exchanger is arranged upstream of the first condenser/heat exchanger as seen in a direction of flow of the refrigerant.

12. The conveyor dishwasher as claimed in claim 11 ,
wherein the third condenser/heat exchanger is arranged downstream of the second condenser/heat exchanger as seen in the direction of flow of the refrigerant.

13. The conveyor dishwasher as claimed in claim 12 ,
wherein the fourth condenser/heat exchanger is arranged upstream of the second condenser/heat exchanger as seen in the direction of flow of the refrigerant.

14. The conveyor dishwasher as claimed in claim 2 ,
wherein the heat exchanger of the waste water heat recovery system is designed to preheat the final rinse liquid, which is to be sprayed in the at least one final rinse zone, from originally 13° C. to 17° C. to 30° C. to 45° C. during operation of the conveyor dishwasher.

15. The conveyor dishwasher as claimed in claim 14 ,
wherein the heat pump device of the waste air heat recovery system is designed to further heat the final rinse liquid, which was pre-heated to 30° C. to 45° C. by the waste water heat recovery system and is to be sprayed in the at least one final rinse zone, to 50° C. to 65° C. during operation of the conveyor dishwasher.

16. The conveyor dishwasher as claimed in claim 1 ,
wherein a heating device which is associated with the at least one final rinse zone is further provided for heating the final rinse liquid which is to be sprayed in the at least one final rinse zone ( 14 ) to or above a previously defined or definable final temperature as required.

17. The conveyor dishwasher as claimed in claim 16 ,
wherein the previously defined or definable final temperature depends on a selected treatment program of the conveyor dishwasher and is at least 65° C. or at least 80° C.

18. The conveyor dishwasher as claimed in claim 16 ,
wherein the heating device which is associated with the at least one final rinse zone is designed to heat the final rinse liquid which is to be sprayed in the at least one final rinse zone to the previously defined or definable final temperature using electrical energy, steam, gas or hot water.

19. A method for operating a conveyor dishwasher which has at least one wash zone and at least one final rinse zone which is arranged downstream of the at least one wash zone as seen in a conveying direction of the washware, wherein the method comprises the following method steps:
i) at least a portion of the thermal energy in the waste water which is to be discha

Assignees

• Disch Harald
• Schrempp Martin
• Illinois Tool Works

Inventors

• Disch Harald
• Schrempp Martin

Classifications

• A47L15/241

  the dishes moving in a horizontal plane · CPC title

• A47L15/4285

  Water-heater arrangements (steam generating arrangements A47L15/4234) · CPC title

• A47L15/48

  Drying arrangements · CPC title

• A47L15/4291 Primary

  Recovery arrangements, e.g. for the recovery of energy or water · CPC title

• A47L15/4214

  Water supply, recirculation or discharge arrangements; Devices therefor · CPC title