Conveyor Ware Washer

Abstract

Conveyor ware washer, comprising of a treatment device (70) for the treatment of sprayed final rinse liquid and/or post wash liquid, resp., so that the treated final rinse liquid and post wash liquid, resp. has the quality of potable water from the microbiological perspective and can be reused as final rinse liquid.

Description

The invention concerns a conveyor ware washer, particularly a commercial conveyor ware washer of the type commonly configured in the form of a flight-type ware washer or in the form of a rack conveyor ware washer.

Conveyor ware washers are known for e.g. from the U.S. Pat. No. 3,789,860, U.S. Pat. No. 4,231,806, DE 196 44 438 C2 and DE 198 29 650 C2.

Two factors largely contribute toward the total consumption of water in case of conveyor ware washers. These factors are the initial filling of the conveyor ware washer with fresh water in all tanks and the use of fresh water for the final rinse while the conveyor ware washer is operating. The final rinse liquid used for the final rinse must be of “potable water quality” in microbiological terms. In the state of the art, this potable water is taken from the building water supply and is completely consumed.

It would be desirable to provide a conveyor ware washer with reduced consumption of fresh water. This aim is achieved by a conveyor warewasher with the features of claim 1 and/or claim 2.

A considerable amount of fresh water will be saved with this invention.

Sprayed final rinse liquid or post-wash liquid is treated in such a manner that it either has the quality of potable water from a microbiological perspective or that it can be mixed in such a proportion with water taken from the building water supply that the resulting water mixture has the quality of potable water in microbiological terms. The treatment of the sprayed final rinse liquid or the post-wash liquid may be done with the help of a micro-filtration system or an ultra-filtration system. Hygiene may guaranteed by the addition of ozone as a disinfecting agent, in case this is necessary in addition to the filtration.

The major difference between micro-filtration and ultra-filtration lies in the different pore sizes and different structures of the micro-filtration and ultra-filtration elements, which are preferably membranes. If they have a pore size of less than 0.1 μm, the filtration is designated as ultra-filtration, whereas filtration with a pore size of more than 0.1 μm to 100 μm is designated as micro-filtration.

An embodiment of the invention is described below with reference to the attached drawings on the basis of examples. The drawings show:

FIG. 1 diagrammatic lateral view of a section from a conveyor ware washer,

FIG. 2 a second embodiment in lateral view,

FIG. 3 a third embodiment in lateral view,

FIG. 4 a fourth embodiment in lateral view,

FIG. 5 a first embodiment of an ozone adding device,

FIG. 6 another embodiment of an ozone adding device,

FIG. 7 one more embodiment of an ozone adding device.

A treatment device as per the invention can either be integrated in the conveyor ware washer or connected to the conveyor ware washer or be located separately.

By way of example, the conveyor ware washers as per the invention given in the drawings can either be rack conveyor ware washers or flight-type ware washers.

According to the drawings, the conveyor ware washers contain at least one wash zone, from which for example two wash zones 3 and 5 are represented, and at least one final rinse zone 25 which, in wash ware transport direction 42, is arranged after the wash zones. The wash zones 3 and 5 each contain a wash system with for example upper wash nozzles 6 and 8 and lower wash nozzles 10 and 12. A wash tank 14 and 16 is provided for each wash zone 3 and 5 for the collection of wash liquid sprayed in wash zone 3 and 5. The wash liquid sprayed by the wash nozzles 6, 10 and 8, 12 resp. of each wash zone 3 and 5 resp. is recirculated by means of a pump 18 and 20 resp. from the respective wash tank 14 and 16 resp. through a wash liquid-supply pipe 19 and 21 resp. again to the wash nozzles 6, 10 and 8, 12.

The final rinse zone 25 contains, for example, the upper final rinse nozzles 24 and lower final rinse nozzles 26. Fresh final rinse liquid can be supplied through a final rinse liquid supply device 28 to the final rinse nozzles 24 and 26. The final rinse liquid supply device 28 can contain a water heater 30, preferably a boiler, a pump 32 and a final rinse liquid supply pipe 27 connecting the pump 32 with the final rinse nozzles 24, 26, and can be connected to a fresh water supply pipe 34.

A transport device 40 conveys the wash ware to be cleaned in transport direction 42, which is shown by an arrow, through the wash zones 3 and 5 and then through the final rinse zone 25.

A dry zone 44 can be provided in the transport direction 42 after the final rinse zone 25, through which the wash ware is transported from the transport device 40. The dry zone 44 is schematically described in FIGS. 1 and 2.

The FIGS. 1, 2 and 3 show an embodiment, for which a post-wash zone 46 is located between the last wash zone 5 and the final rinse zone 25. For e.g. upper post-wash nozzles 50 and lower post-wash nozzles 52 are found in the post-wash zone 46, to which sprayed final rinse liquid is supplied as post-wash liquid from a post-wash tank 54 through a post-wash liquid-supply pipe 56 with the help of a pump 58. The sprayed final rinse liquid in the final rinse zone 25 from the final rinse nozzles 24 and 26, and at least a part of the sprayed post-wash liquid in the post-wash zone 46 from the post wash nozzles 50 and 52 collect in the post-wash tank 54. Another part of the post-wash liquid sprayed from the post wash nozzles 50 and 52 is preferably collected through a conduction element 60 and led into the wash tank 16 of the last wash zone 5.

The post-wash liquid sprayed by the post-wash nozzles 50, 52 in the post-wash zone 46 is therefore re-used final rinse liquid sprayed once in the final rinse zone 25 by the final rinse nozzles 24 and 26. Therefore, the post-wash zone 46 can also be designated as pre-rinse zone 46, the post-wash nozzles 50, 52 can also be designated as pre-rinse nozzles 50, 52 and post-wash liquid can also be designated as pre-rinse liquid.

The final rinse liquid is water which possesses the quality of potable water from the microbiological perspective, with or without an addition of rinse aid.

In FIGS. 1, 2 and 3 the post-wash tank 54 and the wash-tanks 16 and 14 are connected to a liquid-overflow-cascade system, in which the liquid can flow opposite to the transport direction 42 of the transport device 40 from the post-wash tank 54 into the last wash tank 16 and from here to the preceding wash tank 14 etc.

The wash liquid is water, to which the detergent is added.

FIG. 4 is identical to the embodiments as per FIGS. 1, 2 and 3 with the exception that no post-wash zone 46 is provided. Accordingly, FIG. 4 also has no post-wash tank 54, but a floor 62 or floor trough 64 is provided for collection of the final rinse liquid which is sprayed from the final rinse spray nozzles 24 and 26 in the final rinse zone 25, from which the sprayed final rinse liquid can flow into the neighbouring last wash tank 16.

The first wash tank 14 in the transport direction 42, which is the last wash-tank 14 in the flow direction of the liquid cascade, can be provided with a drain 66 for discharge of soiled wash liquid for all embodiments in FIGS. 1, 2, 3 and 4.

According to the invention, all conveyor ware washers as per FIGS. 1, 2, 3 and 4 are provided with a treatment device 70 for treating of sprayed final rinse liquid or for treating a mixture of sprayed final rinse liquid and sprayed post-wash liquid, so that the treated liquid again has the quality of potable water in microbiological terms.

The treatment device 70 is connected to the final rinse zone 25 as per FIG. 4 and to the final rinse zone 25 and the post-wash zone 46 as per FIGS. 1, 2 and 3, so that it gathers in it the sprayed final rinse liquid or a mixture of the sprayed final rinse liquid and post-wash liquid and then returns the treated liquid in the final rinse zone 25 for renewed spraying. The treatment device 70 contains preferably a micro-filtration device 72 or ultra filtration device 72 for filtration of the sprayed final rinse liquid.

As per the preferred embodiments of the invention the micro-filtration device 72 or ultra filtration device 72 contains a transverse flow filter 74 for micro-filtration or ultra-filtration of the sprayed final rinse liquid.

As per the special embodiment of the invention the transverse flow filter 74 contains at least a primary chamber 76 and a secondary chamber 78, which are separated from each other by at least one micro-filtration element 80 or one ultra-filtration element 80.

The invention can be realized in different embodiments. The treated pre-used final rinse liquid depending on the embodiment can either be only sprayed final rinse liquid of the final rinse zone 25 or a mixture of the sprayed final rinse liquid of the final rinse zone 25 and sprayed post-wash liquid from the post wash zone 46 or only post-wash liquid from the post-wash zone 46 (which is pre-used final rinse liquid used again).

The pre-used final rinse liquid to be cleaned flows through the primary chamber 76 with the pressure of a pump from an inlet 82 to an outlet 84, during which a part is filtered through the filtration element 80 and thus reaches in the secondary chamber 78 as cleaned final rinse liquid. This cleaned final rinse liquid can be led back through a discharge pipe 86 into the final rinse liquid-supply device 28, for example into the water heater 30, if from the microbiological perspective it is of potable quality.

For cases where the micro-filtration or ultra-filtration for the production of water which does not satisfy the quality of potable water from the microbiological perspective, ozone can be added as a disinfecting component to the final rinse liquid which was cleaned by the filtration for the purpose of disinfecting. For example, an ozone-adding device 90 can be provided. This can be connected on the one hand with a connecting pipe 92 to the secondary chamber 78 and on the other hand to the discharge pipe 86.

The treatment device 70 contains a gathering pipe 94, through which it gathers the pre-used final rinse liquid to be cleaned, and supplies it to the inlet 82 of the primary chamber 76 of the transverse flow filter 74. The gathering pipe 94 is connected to the post-wash tank 54 in FIGS. 1, 2 and 3, in order to gather not only the sprayed final rinse liquid in the final rinse zone 25, but also at least a part of the sprayed post-wash liquid in the post-wash zone 46. In case of the embodiment of FIG. 4, the gathering pipe 94 is connected to the floor trough 64, in order to gather the sprayed final rinse liquid of the final rinse zone 25.

The un-cleaned final rinse liquid part flowing through the outlet 84 from the primary chamber 76 can be re-used in the dish washing machine. This un-cleaned final rinse liquid can be re-circulated in a circuit as per a preferred embodiment form. There are several embodiments which are possible.

An embodiment option is shown in FIGS. 1 and 4. The intake pipe 94 is connected to the inlet 82 of the primary chamber 76 through a final rinse liquid collection element 100, preferably a collection tank, and a primary chamber inlet pipe 102, which comprises a supply pump 104 feeding into the primary chamber 76. The outlet 84 of the primary chamber 76 is again connected with the final liquid collection element 100 through a primary chamber outlet pipe 106. Thus the re-circulated final rinse liquid from the primary chamber 76 mixes with pre-used final rinse liquid to be cleaned in the final rinse liquid collection element 100. The pre-used final rinse liquid flows through the intake pipe 94 in FIG. 4 only from the final rinse zone 25 and additionally in case of the embodiment as per FIG. 1 from the post-wash zone 46 into the final rinse liquid collection element 100. The pump 104 supplies in direction from the final rinse liquid collection element 100 to the inlet 82 of the primary chamber 76. Thus the primary chamber 76, the final rinse liquid collection element 100 and the pump 104 form a primary chamber re-circulation circuit 108, as is indicated by the arrow 108.

The final rinse liquid collection element 100 can however also be designed as a collection element for the collection of soil particles, which can be taken from the collection element 100 continuously or intermittently.

In case of embodiment of FIG. 2 the post-wash tank 54 is connected through the gathering pipe 94 and a pump 104 in the primary chamber inlet pipe 102 to the inlet 82 of the primary chamber 76, without the use of a final rinse liquid collection element 100. The outlet 84 of the primary chamber 76 is connected through the primary chamber outlet pipe 106 with the post-wash tank 54 in flow connection, in order to lead back the post-wash liquid from the primary chamber 76 into the post-wash tank 54. Thus a primary chamber re-circulation circuit 208 is formed, which contains the pump 104 and in its feeding direction one after the other the primary chamber 76 of the transverse flow filter 74 and the post-wash tank 54.

In case of the embodiment of FIG. 3 the suction side of the pump 58 is connected through the intake pipe 94 with the post-wash tank 54. The pressure side of the pump 58 is connected through the primary chamber inlet pipe 102 with the inlet 82 of the primary chamber 76. The outlet 84 of the primary chamber 76 is connected through the primary chamber outlet pipe 106 with the final wash liquid supply pipe 56 of the post-wash nozzles 50 and 52 of the post-wash zone 46. Thus a primary chamber re-circulation circuit 308 is formed, which contains in the supply direction of the pump 58, consecutively the pump 58, the primary chamber 76, and the post-wash nozzles 50 and 52 and then the post-wash tank 54. Here the pump 58 does not only serve the supply of the pre-used final rinse liquid to be cleaned through the primary chamber 76, but also simultaneously the supply of this final rinse liquid as post-wash liquid to the post-wash nozzles 50 and 52. This embodiment requires one pump less than the embodiments as per FIGS. 1 and 2.

In the drawings, parts corresponding to the same function are provided with the same reference numbers. Features of an embodiment can also be combined with features of the other embodiments and vice versa.

The FIGS. 5, 6 and 7 show different types 190, 290 and 390 of the ozone-adding device 90 as examples as per the invention in order to supply ozone into the filtered final rinse liquid. Arrows 120 and 122 show the filtered final rinse liquid and its flow direction before and after the addition of ozone “O3”.

In case of type 190 of an ozone discharge device 90 from FIG. 5, a storage tank 126 is provided in which ozone “O3” or an ozone air mixture can penetrate through a gas-permeable membrane 130 into the filtered final rinse liquid.

In case of type 290 of an ozone-adding device 90 of FIG. 6 the filtered final rinse liquid flows through a tank 226. A venturi-circuit 228 is connected to the tank 226, in which by a pump 230 filtered final rinse liquid is taken from the tank 226, driven through a venturi element 232 and then again supplied into the tank 226. The filtered liquid flow sucks in ozone “O3” or an ozone-air mixture within the venturi element 232 and then flows back into the tank 226, where the ozone can mix with the remaining part of the filtered final rinse liquid.

In case of the type 390 of an ozone adding device 90 in FIG. 7 a venturi element 332 is located in the flow path of the filtered final rinse liquid from the secondary chamber 78 of the transverse flow filter 74 to the final rinse-supply device 28 for sucking in ozone “O3” or an ozone-air mixture from a source of ozone which is schematically shown in the drawings as “O3”.

Claims

1. A conveyor ware washer comprising at least one wash zone for spraying of wash liquid, at least one final rinse zone for spraying of final rinse liquid on wares, and a post-wash zone for spraying of post-wash liquid on wares between the wash zone and the at least one final rinse zone, a ware conveyor for moving wares through the wash zone, post-wash zone and final rinse zone; characterized by a treatment device for the treatment of sprayed final rinse liquid and sprayed post-wash liquid, so that the treated liquid is of potable quality of water in microbiological terms, whereby the treatment device is made for automatic gathering of sprayed final rinse liquid and sprayed post-wash liquid and for discharge of the treated liquid to the final rinse zone for renewed spraying as final rinse liquid or at least as a portion of final rinse liquid.

2. A conveyor ware washer comprising at least one wash zone for spraying of wash liquid and at least one final rinse zone for spraying of final rinse liquid on wares; characterized by a treatment device for treatment of sprayed final rinse liquid, so that treated final rinse liquid is of potable quality of water in microbiological terms, whereby the treatment device is made for automatic gathering of sprayed final rinse liquid and for discharge of the treated final rinse liquid to the final rinse zone for renewed spraying as final rinse liquid or at least as part of final rinse liquid.

3. The conveyor ware washer of claim 2, characterized in that the treatment device comprises a micro-filtration device or an ultra-filtration device for filtration of the sprayed final rinse liquid of claim 2.

4. The conveyor ware washer of claim 3, characterized in that the micro-filtration device or the ultra-filtration device comprises a transverse flow filter for providing micro-filtration or ultra-filtration.

5. The conveyor ware washer of claim 4, characterized in that the transverse flow filter comprises at least one primary chamber and at least one secondary chamber, which are separated from each other with at least one micro-filtration element or at least one ultra filtration element, the primary chamber is integrated in a primary chamber liquid circuit by which sprayed liquid to be treated is supplied to the primary chamber, and the secondary chamber gathers filtered liquid.

6. The conveyor ware washer of claim 3, characterized in that the treatment device comprises an ozone-adding device for feeding of ozone or an ozone-air mixture into the filtered liquid.

7. The conveyor ware washer of claim 2, characterized in that between the wash zone and the final rinse zone a post-wash zone with post-wash nozzles is located for post washing of wares with post wash liquid in the form of pre-used final rinse liquid, a post-wash tank is provided for gathering final rinse liquid which was sprayed in the final rinse zone and for gathering at least a part of post-wash liquid sprayed in the post-wash zone, that the treatment device is connected to the post-wash tank in order to take therefrom a mixture of the sprayed final rinse liquid and of the sprayed post-wash liquid, for treating it so that it becomes treated final rinse liquid which is of a potable quality of water in microbiological terms.