EP0988825B1 - Screen filter for a water leading machine - Google Patents

Description

The invention relates to a filter screen for a liquid-carrying Household appliance according to the preamble of the claim 1. Such a filter screen is from the Document DE-OS-1 628 645 known, as the closest prior art is seen.

With liquid-carrying household appliances, it is common a working fluid with the help of a filter screen clean. This is the case with a household dishwasher, for example known (DE-OS 44 00 877), a sieve combination for cleaning a circulated rinsing liquid use. The sieve combination essentially comprises a flat screen with a slight inclination to one Center is formed, and a cylindrical, Sieve nozzle open on both sides, with its one opening is coupled to the flat screen center.

The flat screen covers one arranged under a washing container Drain pan. The screen cylinder is in the center of the Drain pan arranged. Flat screen and screen cylinder are assigned to each other in such a way that they have a funnel with a Form frustoconical filler part, the frustoconical Upper part has a very slight slope.

This formation of the sieve combination sets in so-called self-cleaning effect. Because of the inclination of the flat sieve, this is not only covered by liquid Retaining solid particles that are also transported enforced but at the same time by part of the Flushing liquid in a cross flow, which to the center the sieve combination is directed overflows, this Cross flow the retained solid particles to the center of the sieve combination. Located in this center a coarse sieve, which coarsest impurities for prevents manual removal of the same. This one Coarse sieve passing solid particles get with the Part of the rinsing liquid that flows across the flat screen forms, inside the screen cylinder, where it settle and are pumped out after a cleaning process can be. The led into the inside of the screen cylinder Flushing liquid becomes radial in a further filter process passed through the screen jacket of the screen cylinder while doing so cleaned.

Due to the very slight inclination of the surface of the flat screen bumps the self-cleaning effect at a strong contaminated rinsing liquid to its limits. A large proportion of solid particles from the flat screen filtered out, the cross flow is not able to remove the deposits completely. To this The surface sieve gradually clogs up, so that the filter throughput gradually decreases. Is the whole area of the flat screen, this can lead to disturbances in the Operate the device as the circulated rinsing liquid is greatly reduced is.

It is therefore an object of the invention to provide a filter screen for a liquid-carrying household appliance to specify which even if a filter to be filtered is heavily contaminated Working fluid undisturbed operation of the household appliance allows.

The problem is solved with a filter screen according to claim 1. Will be many Filter out solid particles from the filter screen, so store them this on the lower parts of the sieve surface until, in extreme cases, the entire lower one Area is completely covered. Then, however, how before a filtering process over raised areas of the sieve surface respectively. The cross flow increases Solid particles to the filter screen center with.

Preferably not only have the highest digits of the Screen area increases but also their vertical or bevelled side areas on a sieve surface. These increased Zones can have the same sieve structure as the rest Have screen area.

However, to ensure that the dishwasher runs smoothly it makes sense to maintain the sieve structure safely of the raised zones to be made coarser. The still in the rinsing liquid with existing dirt residues pass through this coarse screen area and thus do not cause any covering this increased screen area.

The at least one raised zone can be in the form of ribs be formed on the screen surface. But should one Variety of elevated zones can be set, so the Screen area instead of several arranged ribs instead which take a wave, sawtooth or similar shape. If the filter screen is made of a metal, it can raised zones or the ribs by embossing a sieve plate be attached.

The This can cause the filter screen to self-clean be improved that two or more rib-shaped designed raised zones, the longitudinal axis of the ribs on each a straight line passing through the filter screen center lie, are arranged on the screen surface. As a result of that the working fluid only in the areas between the ribs, the flow rate increases this cross flow, which eventually leads to a ver leads to better cleaning effect. An alternative embodiment the sieve surface, which is all around Circular sectors extending waveform also offers the improved self-cleaning effect described above of the filter screen.

The invention is based on the drawings of an embodiment explained in more detail.

Fig. 1

eine Prinzipskizze eines Sockelbereiches einer Haushalt-Geschirrspülmaschine mit einer Siebkombination;

Fig. 2

ein Flächensieb der Siebkombination gemäß Fig. 1; und

Fig. 3

einen Querschnitt durch das Flächensieb gemäß Fig. 2.

Show:

Fig. 1

a schematic diagram of a base area of a household dishwasher with a sieve combination;

Fig. 2

a flat screen of the screen combination according to FIG. 1; and

Fig. 3

3 shows a cross section through the flat screen according to FIG. 2.

1 is shown at the bottom of a partially Rinsing container 1 of a household dishwasher downward drain pan 2 attached. Their opening to the washing container 1 is from a flat screen 3 and a Coarse sieve 9 covered. Flat screen 3 and coarse screen 9 are Components of a removable sieve combination, which additionally a coarse screen cylinder 9 'and one also includes cylindrical fine screen connector 4.

The flat screen 3 has a circular in its center Breakthrough 10 with a center point 12 to which of the coarse screen cylinder 9 'and the fine screen connection 4 are coupled below are covered by the coarse sieve 9 from above are. At the lowest point of the coarse screen cylinder, which is open towards the bottom 9 'is the intake port of a drain pump 5 connected. Promotes at the end of a washing program the drain pump 5 rinsing liquid, which cleaned Leftovers moved, in a drain system, not shown. At the bottom of the drain pan 2 is an intake manifold a circulating pump 6 in the direction of bearing arranged. A pressure switch 7 with a pressure chamber 8 regulates the fresh water supply to a working level in the rinsing tank 1.

The spray devices not shown by the circulation pump 6 rinsing liquid supplied in the washing container 1 collects after falling back or flowing in the drain pan 2 at the bottom of the washing compartment 1. Before entering a suction area 2 'for the circulating pump 6 becomes the rinsing liquid when passing through the sieve combination 3, 4, 9, 9 'filtered. In order to get into the suction area 2 ', can the flushing liquid a first way through the Flat sieve 3 or a second path through the coarse sieve 9 and then through the coarse screen cylinder 9 'and Take the fine screen connector 4. Filtered out on flat screen 3 Dirt particles are a result of a minor Inclination of the flat screen 3 in the direction of the flat screen center 10, 12 rinsed. If the dirt particles in the La ge are to pass the Gröbstsieb 9, they collect in Inside the coarse screen cylinder 9 'or the fine screen connector 4, where they remain until the pumping process. The also in the inner area of the coarse screen cylinder 9 'and fine screen connector 4 flushing liquid penetrates the sieve surface these two cylindrical, concentric to each other arranged sieves in the radial direction, being here Filtration of the rinsing liquid also takes place.

If the washing liquid is very dirty there is a risk that the screen surface of the flat screen 3 such a large amount of dirt particles from the washing liquid filtered that a transport filtered this No more dirt particles in the filter screen center 10, 12 is possible. In this way, the screen surface moves of the flat screen 3 partially or completely, so that on this reduces the free screen area of the screen combination becomes. This has the consequence that a smaller amount of rinsing liquid fed to the circulation pump for circulation can be. Because of this, they are rib-shaped Elevations 11 arranged on the flat screen 3. These elevations 11 are by an embossing process of the flat screen 3 made of metal attached to this. The rib-shaped Elevations 11 have the same sieve structure as the remaining screen surface of the flat screen 3. The order the elevations 11 is designed such that their Show the longitudinal axis to the center 12 of the filter screen center. From Fig. 3, which is a section through the longitudinal axis shows a rib-shaped elevation 11, is its formation clearly visible.

The rib-shaped elevations 11 cause on the one hand that if the remaining screen surface is covered with dirt particles sufficient free screen area for an undisturbed Circulation operation of the dishwasher available stands. Also, by targeting the increases 11 to the center 12 of the filter screen center 10, 12 achieved that compared to an unstamped Flat screen 3 increased speed of a flow across to the sieve surface, which the filtered off Dirt particles particularly effective to the filter screen center 10, 12 transported. This increased cross flow arises in that the filter screen center 10, 12 flowing liquid around the embossed portion of the Screen area reduced flow area is available.

Claims (8)

1. Screen filter for a water-conducting domestic appliance, which has at least one screen section (3) with a screen surface, the screen section being disposed in a horizontal plane or a plane slightly inclined relative to the horizontal and allowing the passage of liquid, wherein solid particles transported by the liquid may be trapped and the screen surface has at least one area (11) with a position which is proud of the rest of the screen surface, characterised in that some of the liquid flows over the screen surface in a cross-flow and is passed to a screen filter centre (10, 12).
2. Screen filter according to claim 1, characterised in that the raised area (11) of the screen filter has a screen surface over its entirety.
3. Screen filter according to claim 1 or 2, characterised in that the raised area (11) has the same screen structure as the rest of the screen surface.
4. Screen filter according to claim 1 or 2, characterised in that the raised area (11) has a coarser screen structure than the rest of the screen surface.
5. Screen filter according to one of claims 1 to 4, characterised in that the raised area (11) is ridged.
6. Screen filter according to one of claims 1 to 4, characterised in that the screen surface is corrugated, serrated or the like.
7. Screen filter according to one of claims 1 to 6, characterised in that at least two raised zones (11) are formed like ribs and lie on respective straight lines passing through the screen filter centre (10, 12).
8. Screen filter according to one of claims 1 to 6, characterised in that the screen filter has a corrugated form extending continuously over sectors of a circle.

Images