EP1549196B1

EP1549196B1 - Dish washing machine

Info

Publication number: EP1549196B1
Application number: EP03791537A
Authority: EP
Inventors: Bernt Svensson; Kent Karlsson
Original assignee: Asko Cylinda AB
Current assignee: Asko Cylinda AB
Priority date: 2002-08-30
Filing date: 2003-08-29
Publication date: 2011-11-02
Anticipated expiration: 2023-08-29
Also published as: EP1549196A1; WO2004019747A1; AU2003257746A1; DK1549196T3; SE0202590L; SE524021C2; ATE531308T1; SE0202590D0

Abstract

The present invention refers to a dishwasher for batchwise washing of dishes (30) in a container area by means of flushing the dishes with washing liquid by means of flushing nozzles (18, 19, 22, 24, 30). These are attached to a liquid circulation system to circulate the liquid by means of a circulation pump (13), and to cyclically let in and let out the circulating washing liquid. A number of the nozzles are arranged in one or several rotatable flushing arms (17, 21) about an axis. The container area exhibits an intensive zone with a storage area (34) for particularly soiled dishes and an intensive flushing nozzle (30) to direct a local beam towards the intensive zone and its corresponding storage area at a distance from the flushing arm axis (25).

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a dishwasher according to the preamble of appended claim 1.

TECHNICAL BACKGROUND

The invention relates to a type of dishwasher intended for household use, with dishes being washed batchwise in a washing area. Water is supplied to a certain level in the washing area, and is then circulated in a circulation system which comprises one or two flushing arms which are rotatably fixed in the machine for an even covering of the dishes to be washed, which are distributed across the area usually placed in baskets in two layers. An upper arm is arranged between the two baskets, while a lower flushing arm is arranged below the lower basket. The flushing arms exhibit nozzles for flushing of a washing liquid consisting mainly of water, and in a known manner the arms are brought into slow rotation for distribution of the washing liquid. The dishes can be soiled to various degrees, i.e. certain dishes such as pans and pots can require a longer time in order for all of the dirt to be removed. For this purpose, there are special pot programs with a higher number of washing cycles or a higher temperature than that which is used for, for example, delicate dishes. This is energy and time consuming, meaning that even dishes which are lightly soiled will be exposed to the same treatment, i.e. unnecessarily long dishwashing or an unnecessarily high temperature which causes unnecessary wear of the dishes.
Through SE 304 584 B it is earlier known to arrange an extra flushing arm which however is rotating and supported by an attachment in the bottom of the washing area. A rotating flusing arm provides a limited intensity, and furthermore, in this known case an attachment in the steel wall is necessary. US 3,288,155 and DE 195 24 891 11 disclose similar dishwashars.

SUMMARY OF THE INVENTION

The purpose of the present invention is to obtain a lower energy consumption when washing dishes which are highly soiled and which are to be washed together with dishes which are less soiled, without exposing the lesser soiled dishes to exaggerated dishwashing, at the same time as the walls and the bottom of the dishwashing space are kept free from extra attachments.
The said objective is obtained by means of the dishwasher according to the present invention, the characteristics of which will become evident from appended claim 1.
According to the invention, a directed local and intensive flushing is obtained in a chosen limited zone of the dishwasher where highly soiled dishes are placed, without any arrangements in the bottom or the wall of the dishwashing area.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will in the following be described in more detail by means of an example of an embodiment with reference to the appended drawings, where

Fig. 1.: is a partially opened perspective view of a household dishwasher,
Figs. 2 and 3: are perspective views in a larger scale of the inside of the dishwasher according to the invention,
Fig. 4: is a front view of the flushing system of the dishwasher, with certain parts of the flushing system being schematically shown, and
Fig. 5: is a side view of the flushing system, with the rotatable flushing arms being rotated 90° relative to the position of Fig. 4.

A PREFERRED EMBODIMENT

The dishwasher according to the invention is, as can be seen from Fig. 1, designed with a housing 1 which is closed in the operating state, and has a hatch 2 which can be opened for filling and emptying of the dishes which are placed in the baskets 3, 4 (see the dotted lines in Fig. 4) which are arranged in a lower layer and an upper layer. The baskets 3,4 can be moved into and out of a washing area 5 through the opened hatch 2, which is done by means of not shown horizontal guides which are arranged along opposing side walls of the washing area 5. The baskets 3, 4 are open, i.e. provided with large openings so that flushing from the flushing nozzles can take place through the baskets 3, 4 which, for example, are designed by means of networks of plastic ribbons or wire meshes.
As is schematically shown in Fig. 4, the dishwasher is in a conventional manner connected to a pressurized water system via a water intake 6, with a water intake valve 7 being adjustable between an open and a closed position for the supply of water in some positions and no supply during the ongoing washing cycle. Via an outlet conduit 8 , used water or washing liquid is removed, containing both detergent and pollutions. This is done by means of a schematically shown outlet pump 9 which is automatically started after a finished cycle. During an ongoing washing/flushing cycle, the water or the washing liquid is circulated in the washing area 5 in a closed system. In the closed system or circulation system, there is comprised a fluid basin which is formed by a lower container part of the machine for the collection of washing fluid, see the fluid level 10 shown with dotted lines in Fig. 4.
At the bottom of the fluid basin there is arranged a circulation well 12, from which the outlet conduit 8 thus leads. A coarse sieve and a fine sieve cover the well opening upwards. During the washing cycles, the outlet conduit8 is closed either by means of a not shown separate outlet valve, or by means of the outlet pump 9 blocking the outlet conduits in the inactive position
One of the other parts of the closed system or circulatory system is the circulation pump 13 with an electric engine 14 which is arranged to be active during the washing cycles, to circulate the washing liquid under pressure and to be controlled by a not shown control unit for the various process steps of the dishwasher. In the circulation circuit, there is comprised the central canal 15 which extends in the flushing arm tower 16 which supports the rotatable flushing arm 17. said can be of a conventional type, and is rotatably attached about a vertical axis 25 The flushing arm 12 exhibits a plurality of oblique nozzles, both upper nozzles 18 and also nozzles 19 directed downwards. By means of the nozzles being oblique, the arm 12 is driven around for rotation during the operating cycles when the water is pressurized by the circulation pump 13. Via a U-shaped flushing pipe 20, the water or the washing liquid is led to an upper rotatable flushing arm 21, see Figs. 1, 2, 4 and 5, which can be found in most dishwashers for floor mounting in order to, by means of upwardly and also downwardly directed nozzles 22, flush the dishes in the upper basket , but to also flush the dishes in the lower basket 3 and also in a not shown cutlery 3 basket which is usually placed in the lower basket 3 The upper arm 21 is also rotatably fixed and supported by the upper end of the flushing pipe 20 which terminates in an upper flushing arm tower 23 which both leads the water from the flushing pipe 20 to the inside of the flushing arm 21 and also supports the flushing arm's bearing about its axis 25. Water is also led to a cutlery flushing nozzle 24 which is arranged on the upper flushing arm tower 23 and is from above directed towards the cutlery basket for special flushing of cutlery etc.
According to the invention, there is arranged an intensive zone with a storing surface 34 for particularly soiled dishes. To the zone, a stiff unattached flushing arm 26 leads, which consists of a stiff unattached flushing conduit 27 which at its inner end 28 is attached to the lower flushing arm tower 16, and at its outer end supports an intense flushing nozzle 30 which is directed upwards towards the second dish basket 3. The nozzle 30 is arranged at a relatively limited distance from the bottom of the basket 3 which within a chosen zone forms the storing surface 34 for the dishes which are represented by a pot or pan 31 which is turned upside down. The direction and influence of the nozzle 30 is thus limited to a smaller zone of the entire closed washing area 5, as can best be seen in its entirety in Fig. 1. The flushing conduit 27 thus does not exhibit nozzles distributed across the length of the conduit, but is intended to move the flushing point or flushing zone to a location at a distance from the centre of the dishwasher where the cutlery basket is usually placed.
The flushing arm 26 with the flushing conduit 27 is furthermore designed in a stiff material, usually a plastic pipe or a metal pipe , in order to freely support the intensive flushing nozzle 30 at a distance from the bottom or the side walls of the washing area 5 by means of which no mechanical attachments in the wall surfaces of the dishwasher are necessary ; rather the attachment is done directly in the flushing arm tower 16 by means of the conduit 21 protruding into an attachment detail 32 which is arranged on the flushing arm tower 16. In the example shown, the flushing arm 26 is directed obliquely inwards backwards into the washing area as seen from above, in order to form a zone in essentially one of four quadrants which the bottom of the washing area 5 can be considered to be divided into. The intensive flushing nozzle 30 can advantageously be designed in plastic, possibly with a nozzle opening which is covered by a metal pipe , with the nozzle being screwed onto the flushing conduit 27 by means of a locking screw 23. The pipe 22 as such is thus enclosed in its casing surface, but is open at both its ends for the intake of flushing water from the central canal 15 in the flushing tower 16 and for the outlet of the water to the nozzle 30.
The intensive flushing nozzle 30 is in an advantageous example designed so that it emits a beam which diverges from the nozzle 30, so that a normal sized dish 31 positioned directly in front of the beam is hit over a large part of its bottom surface and possibly also to a certain extent its walls. The angle of spread, and thus to a certain extent the amount of flow , also influences the intensity of the beam for which reason a suitable angle is chosen after a normal case. Examples of a possible angle range for the spreading angle is between 45° and 135°, however preferably below 75°. The optimal angle also depends on the distance of the nozzle 20 to the dishes 31, i.e. the storage level of the dish basket 3 in question, i.e. its storing surface 34. Examples of distances are 5-10 cm. Alternatively, it is possible that an evenly distributed beam is replaced by a plume with the shape of a conical casing, but also a highly concentrated rotating beam is possible which thus generates the shape of a conical casing surface.
In the example shown, the free flushing arm 26 is positioned below the rotatable lower flushing arm 17, which in practice is not a problem since the arm 17 passes during such a short part of the flushing time. On the contrary, it can have a positive effect for the cleaning in that a stationary spraying pattern momentarily and recurringly is interrupted and deflected, since at the passage of the lower flushing arm 12, the beam 35 from the flushing nozzle 30 is directed to other areas in the dish 31.
In an advantageous embodiment, the dishwasher can be provided with an alternating valve which, for example, is arranged in the lower flushing tower 16 and which is electrically controlled to alternatingly direct the flow of liquid from the circulating pump 13 to the lower and upper flushing arm 17, 21 respectively. This alternation can be done cyclically at relatively short intervals to obtain maximum liquid pressure in the various flushing nozzles with the use of a certain flow of liquid. The extra flushing nozzles 24, 30 can also be part of this alternation. Alternatively, an alternating valve can be arranged to, as a choice, connect for example the intencive flushing nozzle 30 in case of the presence of extra soiled dishes 31, but can be turned off when there are no such dishes 31. The alternation can also be given a relatively high frequency, so that the beams of liquid accomplish a pulsating effect which gives the liquid an extra dynamic force.
The invention is not limited to the above described examples of embodiments which have also been shown in the drawings but can be freely varied within the scope of the appended claims. It is for example possible to let the non-attached flushing arm 26 be adjustable either by means of the inner attachment 32 making the arm 26 pivotable and/or letting the arm 26 be extendible. The nozzle 30 can also be made rotatable about the longitudinal axis of the arm 26 for adjustment of the direction of the beam 35. It is however essential that the arm 26 has such a stiffness that it can freely support the nozze 30, i.e. freely without any contact with the bottom or side walls, which would lead to the gathering of pollutions.

Claims

A dishwasher for batchwise washing of dishes in a washing area (5) by means of flushing of the dishes with a washing liquid by means of flushing nozzles (18, 19, 22, 24, 30) which are connected to a liquid circulation system in order to circulate the liquid by means of a circulation pump (13), and to cyclically let in and let out the circulating washing liquid, with a number of the nozzles (18,19,22) being arranged in one or several flushing arms (17, 21) rotatable about an axis (25), characterized in that the washing area (5) exhibits an intensive zone with a storing surface (34) for particularly soiled dishes (31), and an intensive flushing nozzle (30) which is arranged to direct a local beam (35) towards the intensive zone and its corresponding storing surface (34) at a distance from said flushing arm axis (25), and in that said intensive flushing nozzle (30) is fixed and attached to a stiff freely supporting flushing arm (26) which both mechanically and regarding the liquid is attached to the circulation conduit at a central canal (15) at the rotatable flushing arm (17), and in that the stiff flushing arm (26) contains a liquid conduit which connects the intensive flushing nozzle (30) with the central canal (15), so that the local beam (35) adapts a certain position and a certain direction .
A dishwasher according to claim 1, characterized in that the flushing arm (26) of the intensive flushing nozzle (30) with its inner end (28) is attached to a flushing arm tower (16) which supports the refatable flushing arm (17) and contains the central canal (15) which communicates with the circulation pump (13).
A dishwasher according to claim 2, characterized in that the intensive flushing nozzle (30) is arranged below the rotatable flushing arm (17).
A dishwasher according to claim 3, characterized in that the rotatable flushing arm (17) is arranged to periodically interrupt and redirect the beam (35) from the intensive flushing nozzle (30).
A dishwasher according to claim 1, characterized in that the storing surface (34) for particularly soiled dishes (31) consists of a chosen place in an open dish basket (3) for inlet of the beam (35) from the intensive flushing nozzle (30).