Dishwashing machine with self-cleaning recirculation filter

Description

[0001] The invention relates to a dishwasher as set forth in the preamble of claim 1. A dishwasher of this kind is known from EP-A-0 068 974.

[0002] Known dishwashers usually have a water collection sump at the bottom of the washing chamber, with a water recirculation pump and a water discharge pump connected thereto.

[0003] The water collection sump communicates with the washing chamberthrough a fine-mesh recirculation filter of a substantially planar configuration adapted to retain particulate matter entrained by the washing water flowing from the chamber towards the collecting sump. The recirculation filter is formed with an opening through which the interior of the washing chamber communicates directly with the intake of the discharge pump. A large-mesh filter inserted into this opening services the main purpose of retaining large particles which might otherwise obstruct or damage the rotor of the discharge pump.

[0004] The dishwasher disclosed in the above-mentioned EP-A-0 068 974 fits with the afore-mentioned design. In addition thereto, the rotating arm, having jet nozzles for directing watertowards the dishes to be washed, is provided with jet nozzles as well directed obliquely downwards onto the surface of the recirculation fitter for rising retained particulate matter off the recirculation filter and sweeping it into the large-mesh pump protection filter. Those additional jet nozzles have a small inclination in the order to 10° to 25°, resulting in a poor efficiency of the jets ejected therefrom. To the contrary, the vertical components of those jets tend to jam the particulate matter into the passages of the recirculation filter, with the result that the filter is progressively obstructed.

[0005] From FR-A-2 302 071 a dishwasher is known having a fine-mesh filter located at the bottom of the washing chamber above a water collecting sump. The washing chamber is provided with a stationary fresh water supply located in a position so as to direct a water jet against the fine mesh filter so that a rinsing flow of water results therefrom extending over the whole surface of the filter.

[0006] It is the object of the present invention to provide a dishwasher as set forth in the preamble of claim 1 having efficient self-cleaning characteristics without requiring particularly complicated auxiliary devices.

[0007] This object is attained by the characterizing features of claim 1. Preferred embodiments of the invention are the subject matter of the dependent claims.

[0008] Due to the water ejecting nozzle being provided at the rotating nozzle carrier arm, the water jet ejected therefrom is able to uniformly extend over the whole filter surface upon rotation of the nozzle carrier arm. The tangential direction of the water jet is effective to avoid that any debris on the filter surface be jammed in the filter openings. Thus, the filter is automatically and effectively cleaned.

[0009] The characteristics and advantages of the invention will become more clearly evident from the following description, given by way of example with reference to the accompanying drawing, the only figure of which shows a diagrammatic parti- cal view of a dishwasher and, at the same time, shows two different embodiments of the invention.

[0010] With reference to the figure, a dishwasher comprises a washing chamber 3 (only partially shown), the bottom of which is formed with a sump 4 for collecting the washing and rinsing water.

[0011] Located in sump 4 is the intake section 2 of a recirculation pump 5 for the supply of water to at least one rotating nozzle carrier arm 6 for spraying the water onto the (not shown) dishes to be washed in the known manner.

[0012] Disposed in washing chamber 3 below nozzle carrier arm 6 is a fine-mesh recirculation filter 7. Filter 7 is disposed in the flow path of the water sprayed onto the dishes and flowing back into sump 4 for being recirculated by pump 5.

[0013] Filter 7 is formed with a frustoconical portion housing a removable large-mesh filter 8 of a suitable shape disposed in the flow path of the water from sump 4 to the intake of a discharge pump 9.

[0014] The dishwasherfurthercomprises nozzle means 10 adapted to direct a jet of water 11 onto the surface of recirculation filter 7 in a direction towards the center of washing chamber 3. According to a characteristic aspect of the invention the water jet 11 ejected from said nozzle means 10 is directed substantially tangentially onto the surface of recirculation filter 7.

[0015] According to one embodiment of the invention shown in the left-hand portion of the drawing this effect may preferably be obtained by means of a substantially annular deflector 13 extending adjacent the periphery of filter 7, itself shaped for instance as an annular sheet member concentric with the axis of rotation of nozzle carrier arm 6.

[0016] In this embodiment nozzle carrier arm 6 has its underside formed with at least one supplementary opening 10 adapted to direct a jet 14 of water onto deflector 13 shaped to deflect the water so as to form tangential jet 11, the latter being aligned in the radial direction of filter 7.

[0017] As already stated it has been experimentally found that jet 11, being substantially devoid of vertical components, does not cause the passages offilter7 to be obstructed by the particulate matter it entrains; quite to the contrary, the particulate matter is swept along the surface of the recirculation filter 7 substantially without hindrance and into large-mesh fitter 8 to be collected therein prior to being expelled therefrom during a subsequent water discharge cycle.

[0018] The invention thus attains the stated object of achieving an effective automatic cleaning of recirculation filter 7 which may advantageously be of a simple construction (for example a simple metal sheet or plastic panel), and may be formed with particularly narrow passages to result in improved filtering performance.

[0019] The described combination results in an improvement of the overall performance of the dishwasher by achieving effective filtering of the total volume of the recirculated water instead of filtering only part of the circulating water as in conventional embodiments.

[0020] In this context it is to be noted that the particularly narrow passages of the recirculation filter facilitate the displacement of particulate matter on the surface of the filter, thus contributing to the self-cleaning effect. It has been experimentally found that the optimum dimension of the passages of filter 7 lie between 0.2 and 0.3 millimeters.

[0021] In an alternative embodiment shown in the right-hand portion of the drawing, deflector 13 may be omitted, jet 11 being produced by a branch pipe 12 extending downwards from nozzle carrier arm 6 and being suitably shaped into an "L" configuration, as shown in the drawing, and terminating in nozzle 10.

[0022] The described dishwasher may of course be subjected to various modifications and alterations within the scope of the invention. The jet 11 issuing from supplementary nozzle 10 may for instance be inclined directly onto filter 7 in the known manner; in this case, however, the recirculation filter would be of substantially conical shape with its surface aligned with respect to jet 11 so that the latter impinges tangentially thereon.

Claims

1. A dishwasher comprising a recirculation filter (7), having a substantially planar surface adapted to retain particulate matter, a rotating nozzle carrier arm (6) disposed above said surface of said recirculation filter (7) and having at least one nozzle (10) for ejecting a water jet (11) for cleaning said surface of said recirculation filter (7) characterized in that means (12; 13) are assigned to said at least one nozzle (10) for establishing that said water jet (11) is directed substantially tangentially onto said surface of said recirculation filter (7) and aligned in a radial direction with respect thereto.

2. A dishwasher according to claim 1, characterized in that said means assigned to said at least one nozzle (10) includes an annular deflector (13) extending adjacent the periphery of the recirculation filter (7) and supplied with water by said nozzle (10).

3. A dishwasher according to claim 1, characterized in that said means assigned to said at least one nozzle (10) comprises at least one branch pipe (12) on the rotating nozzle carrier arm (6) and terminating in said nozzle (10).

4. A dishwasher according to any one of the preceding claims characterized in that said filter (7) is provided with passages having dimensions between 0.2 and 0.3 mm.

Ansprüche

1. Geschirrspülmaschine mit einem Umwälzfilter (7), das eine im wesentlichen planare Oberfläche aufweist und dazu eingerichtet ist, Partikelmaterial zurückzuhalten, einem rotierenden Düsenträgerarm (6), der über der Oberfläche des Umwälzfilters (7) angeordnet ist und wenigstens eine Düse (10) aufweist, um einen Wasserstrahl (11) zum Reinigen der Oberfläche des Umwälzfilters (7) abzugeben, dadurch gekennzeichnet, daß der genannten wenigstens einen Düse (10) eine Einrichtung (12; 13) zugeordnet ist, um zu bewirken, daß der Wasserstrahl (12) im wesentlichen tangential auf die genannte Oberfläche des Umwälzfilters (7) gerichtet und in radialer Richtung bezüglich desselben ausgerichtet ist.

2. Geschirrspülmaschine nach Anspruch 1, dadurch gekennzeichnet, daß die der genannten wenigstens einen Düse (10) zugeordnete Einrichtung einen ringförmigen Ablenker (13) umfaßt, der sich benachbart dem Umfang des Umwälzfilters (7) erstreckt und von der genannten Düse (10) mit Wasser versorgt wird.

3. Geschirrspülmaschine nach Anspruch 1, dadurch gekennzeichnet, daß die der genannten wenigstens einen Düse (10) zugeordnete Einrichtung wenigstens ein Zweigrohr (12) an dem rotierenden Düsenträgerarm (6) umfaßt, der in der genannten Düse (10) endet.

4. Geschirrspülmaschine nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das Filter (7) mit Durchlässen versehen ist, deren Abmessungen zwischen 0,2 und 0,3 mm liegen.

Revendications

1. Lave-vaisselle comportant un filtre de recyclage (7) ayant une surface pratiquement plane adaptée pour retenir les particules de matières, un bras tournant porteur de buses (6) disposé au-dessus de la surface de ce filtre de recyclage (7) et ayant au moins une buse (10) pour projeter un jet d'eau (11) destiné à nettoyer la surface du filtre de recyclage (7), caractérisé en ce que des moyens (12; 13) sont associés à cette(s) buse(s) (10) pour que ce jet d'eau (11) soit dirigé pratiquement tangentiellement sur la surface du filtre de recyclage (7) et soit orienté radialement par rapport à lui.

2. Lave-vaisselle selon la revendication 1, caractérisé en ce que les moyens associés à cette(s) buse(s) (10) comportent un déflecteur annulaire (13) s'étendant adjacent à la périphérie du filtre de recyclage (7) et alimenté en eau par cette buse (10).

3. Lave-vaisselle selon la revendication 1, caractérisé en ce que les moyens associés à cette(s) buse(s) (10) comportent au moins un tube coudé (12) sur le bras tournant support de buses (6) et se terminant en cette buse (10).

4. Lave-vaisselle selon l'une quelconque des revendications précédentes, caractérisé en ce que le filtre (7) a des passages ayant des dimensions comprises entre 0,2 et 0,3 mm.

Drawing