The invention concerns a sieve device for a dishwasher that is placed in the floor of the dishwasher and keeps rough impurities out of the suction area of the circulating pump.
Conventional flat sieves for dishwashers have sieve holes all with the same diameter. If the dishes put into the dishwasher have an impurity made up of a plurality of particles the same size, they can cover large areas of the sieve holes if the size of the impurity residues is approximately in the range of the hole size. This is the case, for example, with coffee grounds, in which the ground coffee particles are not broken down any further during the washing, but have a particle size in the range of the diameter of the sieve hole, depending on how finely they are ground. If the surface of the sieve is covered with these kinds of particles, it can affect the washing results or operation.
The problem of the invention is to design a sieve device for a dishwasher on a dishwasher so that the sieve function is not affected if there is a plurality of small particles of impurities the same size.
The problem is solved with the features in Claim 1 and 15.
Advantageous embodiments are the subject of the subclaims.
According to Claim 1, a sieve device is provided with a large number of sieve holes distributed over the surface of the sieve. The holes are not uniform in size, but are different sizes. For example, the hole size is statistically distributed around a mean hole size, with the hole size deviating above and below. Or there are two or more groups of hole sizes, and the holes in each group are uniform in size.
Using different hole sizes, when the sieve device is in a wash cycle, in which there is a plurality of particles of impurities that are uniform or almost uniform in size prevents the particles from uniformly blocking all of the holes on the surface of the sieve. For example, small particles will cover only the smaller size sieve holes, but will be rinsed through the larger sieve holes. This prevents complete coverage of the sieve device. Or if the particles are larger, only the large sieve holes will be covered by the particles, while the particles that are too big will not fit through the smaller sieve holes, so they will be washed away from the entrance to the smaller sieve holes during the wash cycle.
It is a great advantage for the sieve device to have a surface sieve placed as a filter device in front of the suction hole of the circulating pump of a dishwasher. The advantage is the size (diameter or minimum cross section) from the smallest to the largest hole, in the range of 0.4 mm to 2 mm, and a special advantage in the range from 0.6 mm to 1.2 mm, so that, on one hand, particles up to a certain size can take part in the circulating process, while particles that are too large are kept away from the circulating process during a rinse cycle, for example by collecting the larger particles in a rough/fine sieve.
In one highly advantageous embodiment, the surface of the sieve itself is structured, i.e., compared to a basic sieve surface or plane, there are sieve surfaces that project up or go down.
The basic sieve surface here means the surface that the sieve would take up if there were no structuring. The sieve surface itself can be shaped as a whole, for example, as a funnel-shaped surface, cone-shaped surface, conical surface or the like. Projections and depressions mean a projection or depression compared to that surface. Naturally, there is a certain freedom in the ‘determination’ of the basic sieve surface, whereby, for example, the deepest points of recesses can be accepted as a basic surface or the highest points of the projections as the basic surface, and the structures formed into this fictive basic surface are then accepted as projections and/or depressions.
Structuring the sieve surface helps wash out clogged sieve holes in the higher sieve areas. Sieve holes in the raised areas are preferably larger than sieve holes in the plane of the basic surface. Larger particles of impurities thereby collect preferably in the deeper sieve surface areas and smaller impurities, which are torn apart more easily by the current, fall through the larger sieve holes in the raised areas, so that the sieve holes in the raised areas are predominantly kept free.
A special advantage is the ducts formed by the elevations and/or depressions within the sieve surface that run in the direction of the height gradients of the basic sieve surface. If there are particles of impurities that are too large to go through the sieve holes or if the smaller sieve holes are partly clogged, particles of impurities in the ducts are taken to deeper areas of the sieve surface. Advantageously, there is a hole there in which a rough/fine sieve with large holes is provided, for example, so that the particles of impurities transported in the ducts along the sieve surface go into the rough/fine sieve and are removed by the circulating circuit.
The fact that the cross section of the holes is not round, but polygonal (triangle, square, etc.) helps the wash liquid to drip or flow through the holes. Especially if plastic is used as the basic material of the sieve device or sieve surface, despite the higher adjacent surface tension, this promotes dripping from the plastic sieve into the catch basin under it.
In another embodiment of a sieve device, the sieve device itself is made of plastic or basically of plastic, and the sieve holes have a cross section with at least one edge, in order to take the moisture from the top of the sieve surface to the bottom by capillary action. Here, the holes must not have different sizes, but have only one different size, according to one advantageous embodiment.
One form of embodiment of the invention will be explained using
On the back of the surface sieve 1, there is an indentation 3, with which the surface sieve 1 can be pushed via a connecting support of a lower spray arm. The basic surface 4 of the surface sieve 1 is designed to be slightly funnel-shaped, whereby the central hole 2 represents the deepest point of the surface 4. Around the central hole 2 is a middle area 6 in the plane of the surface 4 (i.e., slightly funnel-shaped or conical running toward the central hole 2). Around the middle area 6 there are flat convex areas 5, which are curved out approximately 3 to 5 mm upward and offset to the basic surface 4. Between the convex areas 5 run grooves 7 in the plane of the basic surface 4, whereby the grooves 7 run radially in the direction of the central hole 2.
As indicated by the surface model in the various surface areas of the surface sieve 1, the diameters of the sieve holes in the different areas are different. In the middle area, the hole diameter is approximately 0.6 mm. In the area of the adjacent basic surface 4, the hole diameter is 0.75 mm. In the area of the convex places 5 and elevations, the hole diameter is 1 or 1.2 mm. The hole density, i.e., the number of holes per unit of surface, is the same in all three surface areas 4, 6, 5. One embodiment provides for the hole density to increase as the hole diameters become smaller.
Number | Date | Country | Kind |
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05007343.6 | Apr 2005 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2006/002748 | 3/25/2006 | WO | 00 | 2/18/2008 |