Improved extractable filter for dishwashing machines

Abstract: The present invention relates to a filter (1) of the extractable type for dishwashing machines, comprising a tapered body, with lateral walls, for the drainage of the washing liquid and with a bottom (5); the principle characteristic of the invention consists in the fact that the bottom (5) is provided with a plurality of openings (7) of such a shape to allow for the drainage of the washing liquid and small particles of residues contained within, whilst retaining the larger residues eventually present in the washing liquid.

Description: The present invention relates to an extractable filter for dishwashing machines, as defined in the preamble of the appended claim 1. Dishwashing machines are known that are provided with filters for avoiding that the residues removed from the dishes be placed in circulation with the washing liquid and deposited again on the dishes. Such filters are normally composed of two filtering elements; one being made of a fine mesh for withholding the small particles of residues, while a second filtering element of a larger mesh being extractable for cleaning purposes, has the task of withholding the larger particles, i.e. pieces of meat, tooth picks or the like, so as to inhibit that such particles go on to block the drainage pump. This kind of second filter, made up of a large mesh for avoiding the hinderance and blockage of the drainage of the washing liquid, is substantially of cylindrical shape and made of plastic material for ease and construction economy. It is open at its superior extremity whilst it may be closed at its inferior extremity having outlets in its cylindrical body. The inferior section can be made closed so as to avoid large residues such as tooth picks or the like, passing through the outlets and being drawn by the drainage pump with the risk of blockage, the consequence of which being drainage hinderence, overheating of the pump's motor, which could also cause it to burn out. This solution providing for the inferior section to be closed, brings into evidence the inconvenience that the small particles of residues are deposited on this surface, which having no outlets for allowing the direct drainage of such residues with the washing water, results in the fact that such residues can be placed in circulation during the rinsing phase and be deposited on the washed dishes. There are known various examples of realisation for avoiding such inconveniences, that call for the utilisation of many components for constructing the filter. In this way however, the filter becomes more complex, expensive and more difficult to clean, as when extracted it is possible that the various components become dismantled, thus causing difficulties for the user that may have problems in its reassembly. For instance, from FR-A-2 378 493 an extractable filter of the above type is disclosed, provided with apertures in the lower part and with a downwardly open chamber in the upper part, with the aim of preventing, during the draining phases of the washing liquid, the backflow of small residues, which could therefore deposit of the fine mesh filter and be recirculated by the washing liquid during a successive washing phase. The embodiments described in FR-A-2 378 493, which are of complex and expensive realization, do not however avoid the possible passage of toothpicks or small bones through the filter, which could cause the blockage of the drain pump, or the falling of the retained residues, during the removal of the filter. From DE-B-1 158 942 is also known a dishwashing machine which is provided with a filtering device arranged in the lower portion of the washing chamber of the machine; said filtering device is formed by a plurality of linked concentric rings which define a series of drain opening, the dimensions of which can be varied upon a command, for two different operating conditions. Also the filtering device disclosed in DE-B-1 158 942 drastically presents the risk of passage of residues being thin but sufficiently long to hinder the correct operation of the drain pump, which can be horizontally conveyed by the washing liquid through said rings; this is due to the fact that the sump of the dishwashing machine does not have a sufficiently restricted section, which would avoid this residues to assume said horizontal position. The aim of the present invention is to indicate a filter for dishwashing machines that does not present the inconveniences of the type known. To allow for such aims the present invention has as its object an extractable filter for dishwashing machines, as defined by the characterising features of the independent claim 1. Other improvements and embodiments of the invention are indicated in the dependent claims Further aims and advantages of the present invention will become clear from the detailed description that follows and from the annexed drawings, supplied as a non-limiting example, wherein: figure 1 represents a sectioned side view of a filter for dishwashing machines according to the invention; figure 2 represents the plan view of a filter for dishwashing machines according to the invention; figure 3 represents a partial sectioned side view of a filter for dishwashing machines according to a variant of the invention; figure 4 represents a sectioned side view of the bottom of a filter for dishwashing machines according to a further variant of the invention. In the figures that represent an extractable type filter for washing machines realised according to the details of the present invention, reference number 1 indicates the filter, realised in stamped plastic material, where outlets 2 are obtained in the cylindrical section due to a plurality of uprights, which allow for the lateral drainage of the washing water; reference number 3 represents protruding wings that allow for the extraction of the filter for cleaning purposes and its placing in a working position; reference number 4 indicates two known means for holding the filter in place during washing; with the reference number 5 the filter bottom in the form of an upturned cone is indicated, made up of a series of concentric flat rings positioned at various levels an held in place with a plurality of uprights, as in the cylindrical section, thus creating a number of outlets 7 that allow for the drainage of the washing water at the lower section. Said concentric rings are realised in such a way the outer circumference of one ring is the same as the internal circumference of the successive ring. In such a way the passage of large food residues is prevented and above all the passage of toothpicks and small bones is prevented that could cause a blockage of the drainage pump, whilst allowing the drainage of the water from the bottom of the filter the cleaning of such is improved and the deposits of residues on the bottom is practically reduced to zero. The characteristics of the filter become clear form the present description and annexed drawings. The advantages of the filter object of the present invention also result in being clear from the present description. In particular they are represented by the fact that: residue deposits do not collect on the bottom of the filter that could be placed in circulation during the rinsing phases and be newly deposited on the dishes that have just been washed; even with rather large outlets in the bottom, the filter prevents residues from passing that could damage the drainage pump; the filter is realised with one single component and its construction is extremely simple and economic. It is clear that numerous variants are possible to the filter for dishwashing machines, object of the present invention, one of which could be that represented in figure 3 where the bottom of the filter can be realised in the form of a cone with its point facing upwards. Another variant of the filter for dishwashing machines could be that represented in figure 4 in which the level of the concentric rings of the bottom are inclined towards the bottom, so as to facilitate the passage of the particles of residues and in preventing them from depositing, thoroughly, on the concentric rings.

Claims: An extractable filter (1) for dishwashing machines, comprising a tapered body with lateral walls and a bottom (5), said body (5) being obtained in a single piece in plastic material, said bottom (5) being provided with a plurality of openings (7), whereby said lateral wall of said body presents a plurality of apertures (2) and said bottom (5) has a substantially conical section characterized in that said bottom is directly connected to said lateral walls (2), said bottom (5) being obtained through a plurality of concentric rings (6) being fixed, flat and laying at different levels, the external circumference of a ring (6) being the same as the internal circumference of the successive ring, all said openings being almost perpendicular in respect of the vertical axis of the filter. Extractable filter, according to claim 1, characterized in that the plane of said concentric rings (6), is inclined with respect the horizontal plane of the filter. A dishwashing machine, comprising the extractable filter according to claim 1.

Inventors: OLIVIERI GAETANO, PREMOLI MARCELLO, OLIVIERI, GAETANO, PREMOLI, MARCELLO
Applicants: MERLONI ELETTRODOMESTICI SPA, MERLONI ELETTRODOMESTICI S.P.A.
Application year: 1992
Main classification: A47L15
IPC codes: A47L15