DE9312801U1 - Sieve combination for a dishwasher - Google Patents

Description

Description

Filter combination for a dishwasher

The innovation concerns a sieve combination for a dishwasher with a collection pot on the bottom of the washing container, which is divided into a suction chamber for the circulation pump and a drain shaft for the drain pump, whereby the suction chamber is covered by a fine sieve and the drain shaft, if necessary, by a coarse sieve and both chambers are separated from each other by a very fine sieve of the sieve combination, which is designed with fixed sieve end parts that form upper and lower drain shaft openings.

It is known that when washing dishes, if there is a lot of dirt, the strain on the sieves increases, so that food scraps falling into the drainpipe are drawn to the sieve walls of the fine sieve by the suction of the circulation pump and sometimes become stuck to the sieve edges of the sieve hole cross-sections in such a way that they cannot be completely removed even by the automatic self-cleaning effect of the sieves that starts when the washing liquid is pumped out. Fine sieves for filtering out microfine dirt usually consist of a wire mesh with mutually overlapping woven round wires that only lie loosely on top of each other. As a result of the round and loose sieve wires overlapping at the intersection points, fine dirt can get caught and matted on the sieve edges of the sieve hole cross-sections, so that the dirt progresses very quickly, causing further sieve hole cross-sections to become blocked. An optimal rinsing result can often no longer be achieved due to the increased self-contamination of the fine sieve casing.

However, in the case of the above-mentioned problem, the respective design of the fine sieve in terms of shape and arrangement in the collecting pot is also a decisive factor. For example, a conical sieve (see DE-OS 42 36 931) with a sieve body that widens conically towards the connection piece of the drain pump, which has fixed sieve end parts at the end for a tight seal on the upper fine sieve and on the drain shaft, has the advantage over sieves with hollow cylindrical sieve bodies (see DE-OS 24 51 822) that when the rinsing liquid is conveyed or pumped out of the rinsing container, the particles adhering to the fine sieve walls are removed.

The resulting dirt particles can fall freely down to the drain pump without coming into contact with the sieve and can be easily removed there. This does indeed support the self-cleaning effect of the conical fine sieve, but the disadvantage remains that fine food residues get caught on the sieve due to the gaps in the sieve wire and become matted there. Overloaded sieve systems, however, force the device operator to check the sieve at very short intervals in order to ensure a good rinsing result.

Another disadvantage of using a fine sieve made of round sieve wires is that the overlapping woven round wires or the round wire mesh are not surface-stable. On the one hand, this means that the sieve mesh bulges even under slight mechanical pressure, which may increase the mesh size and allow food residues to be filtered out to penetrate the damaged fine sieve casing and enter the circulation circuit. On the other hand, it is not easy to attach a sieve casing made of loosely laid wire mesh to the bottom of the collecting pot in a detachable manner, e.g. using a screw or bayonet connection, for the purpose of checking the sieve or similar. When screwing or similar, the sieve body can quickly bend due to the lack of surface stability.

The innovation is based on the task of increasing the dirt load capacity of the fine sieve as well as its filtering effect and mechanical resilience and optimizing the filter self-cleaning.

The stated problem is solved in accordance with the innovation by the features of protection claim 1.

Advantageous embodiments of the innovation can be found in the subclaims.

By using a fine sieve with a sieve shell that widens conically towards the bottom of the collecting pot, whereby the sieve shell consists of calendered sieve fabric, the effective sieve surface of the fine sieve shell is increased - compared to a cylindrical fine sieve body, for example - and the load-bearing capacity of the fine sieve is increased, as well as the effective surface of the upper fine sieve in the bottom of the washing container being increased. Furthermore, because the water generated when the washing liquid is conveyed or pumped out of the washing container,

The self-cleaning effect of the sieves is supported by the fact that the dirt particles adhering to the fine sieve walls can fall freely down to the drain pump without any further contact with the sieve and can be removed there, practically under the effect of gravity. In the innovative combination with the truncated cone-shaped fine sieve, the design of the sieve casing from calendered sieve fabric brings further advantages. The interwoven round wire threads of the fine sieve are slightly flattened by the calendering process at the points where they cross each other and pressed together in such a way that rinsed-off dirt can no longer get caught on the fine sieve and mat there. Self-contamination of the sieve surfaces is advantageously prevented. The effective filter cross-section of the fine sieve is fully retained over time. When the rinsing liquid is pumped out, food residues can be easily and completely rinsed off the calendered sieve basins, so that optimal filter self-cleaning is ensured. The calendering process also ensures that the wire mesh has a stable surface. This means that the fine sieve casing can be easily and detachably mounted on the collecting pot using its sieve end pieces. This makes manual sieve inspections easier. When installing and removing the sieves, the mechanical pressure exerted does not have a negative impact on the fine sieve due to the increased surface stability of the fine sieve body. An increase in the sieve mesh size or bulging of the sieve casing is therefore no longer to be expected.

The following description serves to explain the subject of the innovation, an example of which is shown in the drawing.

The collecting pot (1) shown in longitudinal section, arranged as is known in the bottom of the washing container of a dishwasher (not shown), is equipped with a connection piece (2 or 3) for a circulation pump and for a drain pump, as well as with a sieve combination (4) made up of several separate sieves, with a flat fine sieve (5) covering the suction chamber (6) for the circulation pump (not shown) and a coarse sieve (7) covering the drain shaft (8) for the drain pump (also not shown). Both chambers are separated from one another by a fine sieve (9) of the sieve combination (4) for filtering out fine food residues from the circulated washing liquid in the drain shaft (8). The coarse sieve (7) detachably inserted into the drain shaft (8) can be omitted if necessary. The coarse sieve (7) is located either in the lower or in the

upper part of the drain shaft (8) and is attached to the fine sieve body by a screw, plug or snap connection.

The fine sieve (9) separating the suction chamber (6) from the discharge shaft (8) widens conically towards the bottom of the collecting pot (10) and is shaped like a truncated cone or pyramid. The sieve casing (9a) of the fine sieve (9) consists of interwoven round wire threads, although this sieve fabric is calendered. The illustration shows an enlarged partial section of the sieve fabric (15) of the fine sieve (9) treated by the calendering process.

The sieve casing (9a) of the fine sieve (9) is firmly connected at the top and bottom to plastic sieve end parts (9b or 9c) which form the upper and lower drain shaft openings (11 or 12). The fine sieve (9) with the sieve end parts (9b, 9c) forms the drain shaft (8) in the collecting pot (1). The upper sieve end part (9b) is tightly adjacent to the fine sieve (5) and the lower sieve end part (9c) is tightly adjacent to the collecting pot base (10) or to the connection piece (3) of the drain pump. When installed, the upper sieve end part (9b) covers the fine sieve (5) in the edge area of the upper drain shaft opening and can be detached from the fine sieve (5) if necessary. The sieve combination (4) consisting of fine, coarse and very fine sieves (9) is detachably attached to the bottom of the collecting pot (10) or to the connection piece (3) of the emptying pump via the lower sieve end part (9c) for the purpose of sieve control or the like. For this purpose, the lower sieve end part (9c) has fastening elements (not shown in detail) such that, for example, a snap-in, screw or bayonet connection can be implemented. The bottom of the collecting pot (10) has the same elements.

Separate flushing water flow openings (13) are formed in the lower sieve end part (9c) of the fine sieve (9) in the area of the adjacent collecting pot base (10) or in the sealing area, which connect the suction chamber (6) for the circulation pump with the drain shaft (8). The flushing water flow openings (13) on the lower sieve end part (9c) preferably correspond in cross-section to the sieve hole cross-sections of the fine sieve (5). The flushing water flow openings (13) are forced to function as a valve, such that a flow of flushing water from the suction chamber (6) of the circulation pump to the drain shaft (8) of the drain pump is possible during the pumping process, but is prevented in the opposite direction during flushing water circulation operation. In circulation operation (see solid arrows), the water retained by the fine sieve (5) is discharged into the drain shaft (8).

Food residues washed into the shaft (8) from the dirt collection chamber (14) are partially sucked up to the flow openings (13) of the lower sieve end section (9c), which are thereby closed. When the rinsing liquid is pumped out (see dashed arrows), the food residues are sucked out again without leaving any residue and the rinsing water flow openings (13) are flushed out. This also sucks out any fine dirt that has penetrated into the suction chamber (6) for the circulation pump during circulation operation without leaving any residue, so that the fine sieves (5, 9) are clean when the water is changed again.

During a washing process, a main flow of the washing liquid dripping from the dishes and containing food residues passes through the fine sieve (5) in circulation mode, whereby this sieve filters out small dirt particles and the coarse sieve (7) arranged in the drain shaft (8) filters out the larger dirt particles from the circulated washing liquid. A smaller secondary washing water flow coming from the drain shaft (8) is sucked through the fine sieve (9) into the suction chamber (6) of the circulation pump, whereby small food residues are retained by the fine sieve (9). The filtered washing liquid then returns to the circulation pump circuit. When the washing liquid is pumped out according to the known partial washing programs pre-wash, cleaning, intermediate and final rinse, washing water is sucked back from the suction chamber (6) into the drain shaft (8), whereby the fine sieve (9) is rinsed clean. The reversal of the cycle causes the sieve to self-clean.

The drain shaft openings mentioned at the beginning of the frustoconical fine sieve (9) have different opening dimensions. The opening with the smallest opening dimension determines the upper drain shaft opening of the sieve combination (4). The conical shape of the fine sieve casing (9a) which widens in the direction of the collecting pot base (10) results in an increase in the effective sieve surface of the fine sieve (9) while the flow space remains almost the same. The effective surface of the fine sieve (5) is also increased so that lower flow rates are achieved on the sieve surfaces during circulation, which counteracts the accumulation of dirt on the sieve surfaces. When pumping out the rinsing liquid, accumulated dirt particles have the possibility of falling through immediately to the connection piece (3) of the drain pump without further contact with the fine sieve walls due to the continuously expanding opening cross-section of the truncated cone.

In combination with the fine sieve (9) arranged or aligned as described above, the formation of the fine sieve casing (9a) made of calendered sieve fabric ensures optimal self-cleaning of the fine sieve (9) during pumping. The interwoven round wire threads of the fine sieve fabric (15) are slightly flattened and shaped by the calendering process at the points where they cross each other and pressed together without gaps, so that fine, very fine and coarse dirt rinsed off the dishes can no longer get caught on the fine sieve (9), deposit and mat there. Any loosely deposited dirt particles are quickly and easily rinsed off the sieve basins (16) during the pumping process. The calendering process not only reduces the thickness of the wire mesh, but also ensures that the surface of the sieve is stable so that it cannot bulge during manual sieve checks when installing and removing it. The calendering process also prevents the mesh size of the fine sieve (9) from increasing in a disadvantageous way when pressure is applied from the outside. In order to be able to carry out cleaning and maintenance work on the sieve combination (4) very easily and simply, in addition to the detachable fastening of the sieve combination (4) in the collecting pot (1), it is also advantageous to attach handle elements (17) to the sieves.

Claims (3)

Protection claims 1. Sieve combination for a dishwasher with a collecting pot on the washing tank base, which is divided into a suction chamber for the circulation pump and a drain shaft for the drain pump, whereby the suction chamber is covered by a fine sieve and the drain shaft, if necessary, by a coarse sieve and both chambers are separated from each other by a very fine sieve of the sieve combination, which is designed with fixed sieve end parts that form upper and lower drain shaft openings, characterized, that the fine sieve (9) separating the suction chamber (6) from the discharge shaft (8) widens conically towards the bottom of the collecting pot (10) and is shaped like a cone or truncated pyramid, and that the sieve casing (9a) of the fine sieve (9) consists of calendered sieve fabric (15). 2. Sieve combination for a dishwasher according to claim 1, characterized in that that the sieve combination (4) is attached to the collecting pot (1) via the lower sieve end part (9c), whereby the lower sieve end part (9c) seals tightly with the collecting pot base (10) and is provided in this area with flushing water flow openings (13) which connect the suction chamber (6) for the circulation pump with the drain shaft (8), and that the flushing water flow openings (13) in cross section preferably correspond to the sieve hole cross sections of the fine sieve (5). 3. Sieve combination for a dishwasher according to claim 1 and 2, characterized in that that the fine sieve (5) is, if necessary, removably fixed to the upper sieve end part (9b) and an existing coarse sieve (7) of the sieve combination (4) is fastened in the lower or upper part of the fine sieve base body or the drain shaft (3), and that the sieve combination (4) is detachably fastened to the collecting pot base (10) via the lower sieve end part (9c).